{"id":91168,"date":"2026-08-07T07:24:35","date_gmt":"2026-08-06T23:24:35","guid":{"rendered":"https:\/\/www.wsisp.com\/helps\/91168.html"},"modified":"2026-08-07T07:24:35","modified_gmt":"2026-08-06T23:24:35","slug":"day-24-25-%e5%b9%b6%e5%8f%91%e6%9c%8d%e5%8a%a1%e5%99%a8-io%e5%a4%8d%e7%94%a8%ef%bc%9a%e8%ae%a9%e4%bd%a0%e7%9a%84%e7%a8%8b%e5%ba%8f%e5%90%8c%e6%97%b6%e6%9c%8d%e5%8a%a1%e6%88%90%e5%8d%83%e4%b8%8a","status":"publish","type":"post","link":"https:\/\/www.wsisp.com\/helps\/91168.html","title":{"rendered":"Day 24-25 \u5e76\u53d1\u670d\u52a1\u5668 + IO\u590d\u7528\uff1a\u8ba9\u4f60\u7684\u7a0b\u5e8f\u540c\u65f6\u670d\u52a1\u6210\u5343\u4e0a\u4e07\u4e2a\u201c\u5ba2\u4eba\u201c"},"content":{"rendered":"

\u5355\u8fde\u63a5\u7684 Echo \u670d\u52a1\u5668\u5c31\u50cf\u4e00\u5bb6\u53ea\u6709\u4e00\u4e2a\u670d\u52a1\u5458\u7684\u9910\u9986\u2014\u2014\u5ba2\u4eba\u6765\u4e86\u5f97\u6392\u961f\u7b49\u3002\u4eca\u5929\u6211\u4eec\u7ed9\u9910\u5385\u62db\u6ee1"\u670d\u52a1\u5458"（\u8fdb\u7a0b\/\u7ebf\u7a0b），\u518d\u7ed9\u6bcf\u4e2a\u4eba\u914d\u4e0a\u4e00\u90e8"\u667a\u80fd\u5bf9\u8bb2\u673a"（epoll），\u8ba9\u5ba2\u4eba\u4eec\u968f\u5230\u968f\u5403，\u540c\u65f6\u8fd8\u80fd\u76d1\u63a7\u540e\u53a8\u3001\u6536\u94f6\u53f0\u3001\u5916\u5356\u7a97\u53e3，\u771f\u6b63\u5b9e\u73b0\u591a\u9762\u624b\u3002<\/p>\n

\n

\u524d\u8a00<\/h3>\n

\u5728 Day 22-23 \u4e2d，\u6211\u4eec\u5b9e\u73b0\u4e86\u4e00\u4e2a\u6807\u51c6\u7684 TCP Echo \u670d\u52a1\u5668\u3002\u4f46\u5b83\u6709\u4e00\u4e2a\u81f4\u547d\u7684\u7f3a\u9677：\u4e00\u6b21\u53ea\u80fd\u670d\u52a1\u4e00\u4e2a\u5ba2\u6237\u7aef\u3002<\/p>\n

\u901a\u4fd7\u7c7b\u6bd4：\u60f3\u8c61\u4f60\u5f00\u4e86\u4e00\u5bb6\u5916\u5356\u5e97，\u5e97\u91cc\u53ea\u6709\u4f60\u4e00\u4e2a\u4eba\u3002\u4f60\u63a5\u4e86\u4e00\u4e2a\u7535\u8bdd（accept），\u7136\u540e\u5f00\u59cb\u7b49\u5bf9\u65b9\u62a5\u83dc\u540d（read）\u3002\u5982\u679c\u5bf9\u65b9\u78e8\u78e8\u8e6d\u8e6d\u4e0d\u8bf4\u8981\u4ec0\u4e48，\u4f60\u5c31\u4e00\u76f4\u63e1\u7740\u7535\u8bdd\u5e72\u7b49\u2014\u2014\u540e\u9762\u7684\u7535\u8bdd\u6839\u672c\u63a5\u4e0d\u8fdb\u6765\u3002\u8fd9\u5c31\u662f"\u963b\u585e"\u7684\u56f0\u5883\u3002<\/p>\n

\u4eca\u5929，\u6211\u4eec\u5206\u4e09\u6b65\u8de8\u8d8a\u8fd9\u9053\u574e：<\/p>\n

  • \u591a\u8fdb\u7a0b\u670d\u52a1\u5668（Fork）：\u6bcf\u6765\u4e00\u4e2a\u5ba2\u4eba，\u5c31\u96c7\u4e00\u4e2a\u4e34\u65f6\u5de5\u53bb\u670d\u52a1\u5b83\u3002<\/li>\n
  • \u591a\u7ebf\u7a0b\u670d\u52a1\u5668（Pthread）：\u4e0d\u7528\u96c7\u4eba，\u7528"\u5206\u8eab\u672f"（\u7ebf\u7a0b），\u6bcf\u4e2a\u5206\u8eab\u53bb\u8ddf\u4e00\u4e2a\u5ba2\u4eba\u804a\u5929\u3002<\/li>\n
  • IO \u590d\u7528\u6280\u672f（select \/ poll \/ epoll）：\u4e0d\u96c7\u4eba\u3001\u4e0d\u5206\u8eab，\u7ed9\u4e00\u4e2a\u4eba\u914d\u4e0a\u4e00\u53f0"\u591a\u9891\u9053\u5bf9\u8bb2\u673a"，\u540c\u65f6\u76d1\u63a7\u6240\u6709\u5ba2\u4eba，\u8c01\u5f00\u53e3\u5c31\u8ddf\u8c01\u804a\u2014\u2014\u4e00\u4e2a\u670d\u52a1\u5458\u641e\u5b9a\u5168\u573a\u3002<\/li>\n
    \n

    \u7b2c\u4e00\u90e8\u5206：\u4e3a\u4ec0\u4e48\u5355\u7ebf\u7a0b\/\u5355\u8fdb\u7a0b\u670d\u52a1\u5668\u4e0d\u884c？<\/h3>\n

    \u6211\u4eec\u5148\u56de\u987e\u4e00\u4e0b\u5355\u7ebf\u7a0b\u670d\u52a1\u5668\u7684\u6838\u5fc3\u4ee3\u7801：<\/p>\n

    while (1) {
    \n client_fd = accept(server_fd, …); \/\/ \u963b\u585e\u7b49\u5f85：\u6ca1\u4eba\u6765\u5c31\u4e00\u76f4\u7b49
    \n \/\/ \u26a0\ufe0f \u53ea\u6709\u5f53\u524d\u5ba2\u6237\u7aef\u65ad\u5f00\u540e，\u624d\u80fd\u63a5\u4e0b\u4e00\u4e2a！
    \n while ((n = read(client_fd, buffer, …)) > 0) {
    \n write(client_fd, buffer, n); \/\/ \u963b\u585e\u7b49\u5f85：\u5bf9\u65b9\u6ca1\u53d1\u9001\u6570\u636e\u5c31\u4e00\u76f4\u7b49
    \n }
    \n close(client_fd);
    \n}<\/p>\n

    1.1 "\u963b\u585e"\u5230\u5e95\u662f\u4ec0\u4e48？<\/h4>\n

    \u901a\u4fd7\u7c7b\u6bd4：\u4f60\u53bb\u53d6\u6b3e\u673a\u53d6\u94b1，\u524d\u9762\u7684\u4eba\u64cd\u4f5c\u5f88\u6162\u3002\u4f60\u4e0d\u80fd\u540c\u65f6\u5e2e\u540e\u9762\u7684\u4eba\u53d6\u94b1，\u53ea\u80fd\u7ad9\u7740\u5e72\u7b49\u3002\u8fd9\u5c31\u662f\u963b\u585e\u2014\u2014\u4f60（\u8fdb\u7a0b）\u88ab"\u5361"\u4f4f\u4e86\u3002<\/p>\n

    \u4ece\u64cd\u4f5c\u7cfb\u7edf\u89d2\u5ea6\u770b：<\/p>\n\n\n\n\n\n\n
    \u72b6\u6001<\/td>\n\u8fdb\u7a0b\u5728\u5e72\u561b<\/td>\n\u5360CPU\u5417<\/td>\n<\/tr>\n
    \u8fd0\u884c\u6001<\/td>\n\u6b63\u5728CPU\u4e0a\u6267\u884c\u4ee3\u7801<\/td>\n\u5360<\/td>\n<\/tr>\n
    \u5c31\u7eea\u6001<\/td>\n\u51c6\u5907\u597d\u4e86，\u7b49CPU\u8f6e\u5230\u6211<\/td>\n\u4e0d\u5360<\/td>\n<\/tr>\n
    \u963b\u585e\u6001（\u7761\u7720\u6001）<\/td>\n\u5728\u7b49\u67d0\u4e2a\u6761\u4ef6（\u6570\u636e\u5230\u8fbe\u3001\u8fde\u63a5\u5230\u6765），\u6761\u4ef6\u6ee1\u8db3\u524d\u65e0\u6cd5\u8fd0\u884c<\/td>\n\u4e0d\u5360<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

    \u5173\u952e\u7406\u89e3：\u963b\u585e\u5e76\u4e0d\u4f1a\u6d6a\u8d39 CPU（CPU \u4f1a\u53bb\u6267\u884c\u5176\u4ed6\u8fdb\u7a0b），\u4f46\u5b83\u6d6a\u8d39\u4e86\u673a\u4f1a\u2014\u2014\u56e0\u4e3a\u8be5\u8fdb\u7a0b\u65e0\u6cd5\u53bb\u5904\u7406\u5176\u4ed6\u5ba2\u6237\u7aef\u7684\u8bf7\u6c42\u3002\u8fd9\u5c31\u662f\u5e76\u53d1\u8981\u89e3\u51b3\u7684\u6839\u672c\u77db\u76fe\u3002<\/p>\n

    \n

    \u7b2c\u4e8c\u90e8\u5206：\u591a\u8fdb\u7a0b\u5e76\u53d1\u670d\u52a1\u5668（Fork \u6a21\u578b）<\/h3>\n

    2.1 \u6838\u5fc3\u601d\u60f3\u2014\u2014\u4e00\u5f20\u56fe\u770b\u61c2<\/h4>\n

    \u7236\u8fdb\u7a0b（\u8fce\u5bbe\u5458）
    \n \u2502
    \n \u251c\u2500\u2500 accept() \u2190 \u6765\u5ba2\u4eba\u4e86！
    \n \u2502
    \n \u251c\u2500\u2500 fork() \u2192 \u5b50\u8fdb\u7a0b1（\u670d\u52a1\u54581）\u2192 \u670d\u52a1\u5ba2\u6237A \u2192 \u9000\u51fa
    \n \u2502
    \n \u251c\u2500\u2500 accept() \u2190 \u53c8\u6765\u4e00\u4e2a！
    \n \u2502
    \n \u251c\u2500\u2500 fork() \u2192 \u5b50\u8fdb\u7a0b2（\u670d\u52a1\u54582）\u2192 \u670d\u52a1\u5ba2\u6237B \u2192 \u9000\u51fa
    \n …<\/p>\n

    \u901a\u4fd7\u7c7b\u6bd4：\u94f6\u884c\u5927\u5802\u7ecf\u7406（\u7236\u8fdb\u7a0b）\u53ea\u7ba1\u63a5\u5f85\u548c\u5206\u6d41，\u6bcf\u6765\u4e00\u4e2a\u5ba2\u6237\u5c31\u558a\u4e00\u4e2a\u67dc\u5458（\u5b50\u8fdb\u7a0b）\u4e13\u95e8\u670d\u52a1\u3002\u7ecf\u7406\u81ea\u5df1\u9a6c\u4e0a\u56de\u5934\u63a5\u5f85\u4e0b\u4e00\u4f4d\u3002<\/p>\n

    2.2 \u73af\u5883\u51c6\u5907<\/h4>\n

    \u7b2c 1 \u6b65 \u2192\u00a0\u786e\u8ba4\u4f60\u7684 Linux \u73af\u5883\u5df2\u7ecf\u88c5\u597d gcc：<\/p>\n

    # \u68c0\u67e5 gcc \u662f\u5426\u5b89\u88c5
    \ngcc –version<\/p>\n

    # \u5982\u679c\u6ca1\u88c5（Ubuntu\/Debian）
    \nsudo apt install gcc -y<\/p>\n

    # \u5982\u679c\u6ca1\u88c5（CentOS\/RHEL）
    \nsudo yum install gcc -y<\/p>\n

    \u7b2c 2 \u6b65 \u2192\u00a0\u521b\u5efa\u9879\u76ee\u76ee\u5f55\u5e76\u8fdb\u5165：<\/p>\n

    mkdir -p ~\/linux_study\/day24-25 && cd ~\/linux_study\/day24-25<\/p>\n

    2.3 \u7f16\u5199\u4ee3\u7801<\/h4>\n

    \u7b2c 3 \u6b65 \u2192\u00a0\u7528\u7f16\u8f91\u5668\u521b\u5efa\u00a0fork_server.c：<\/p>\n

    vim fork_server.c # \u4e5f\u53ef\u7528 nano \u6216 gedit<\/p>\n

    \u7b2c 4 \u6b65 \u2192\u00a0\u8f93\u5165\u5b8c\u6574\u4ee3\u7801（\u4e0b\u9762\u6bcf\u4e00\u884c\u00a0\/\/\u00a0\u6ce8\u91ca\u90fd\u8bf7\u4f60\u8ba4\u771f\u8bfb，\u8fd9\u4e9b\u6ce8\u91ca\u5c31\u662f\u4f60\u7684"\u4e2d\u6587\u8bf4\u660e\u4e66"）：<\/p>\n

    #include <stdio.h> \/\/ \u6807\u51c6\u8f93\u5165\u8f93\u51fa，printf \u9700\u8981
    \n#include <stdlib.h> \/\/ \u6807\u51c6\u5e93，exit \u9700\u8981
    \n#include <string.h> \/\/ \u5b57\u7b26\u4e32\u51fd\u6570，memset \u9700\u8981
    \n#include <unistd.h> \/\/ POSIX API，fork \/ close \/ read \/ write \u9700\u8981
    \n#include <sys\/socket.h> \/\/ \u5957\u63a5\u5b57\u51fd\u6570，socket \/ bind \/ listen \/ accept \u9700\u8981
    \n#include <netinet\/in.h> \/\/ sockaddr_in \u7ed3\u6784\u4f53，\u5b58\u50a8 IP \u548c\u7aef\u53e3
    \n#include <arpa\/inet.h> \/\/ inet_ntoa，\u628aIP\u7684\u6570\u5b57\u683c\u5f0f\u8f6c\u6210\u53ef\u8bfb\u5b57\u7b26\u4e32
    \n#include <sys\/wait.h> \/\/ waitpid，\u56de\u6536\u5b50\u8fdb\u7a0b\u7528
    \n#include <signal.h> \/\/ signal，\u6ce8\u518c\u4fe1\u53f7\u5904\u7406\u51fd\u6570<\/p>\n

    #define PORT 8080 \/\/ \u670d\u52a1\u5668\u76d1\u542c\u7aef\u53e3，\u53ef\u6539\u6210\u4f60\u559c\u6b22\u7684
    \n#define BUFFER_SIZE 1024 \/\/ \u63a5\u6536\u7f13\u51b2\u533a\u5927\u5c0f，1KB \u591f\u7528<\/p>\n

    \/\/ \u4fe1\u53f7\u5904\u7406\u51fd\u6570：\u5f53\u5b50\u8fdb\u7a0b\u9000\u51fa\u65f6，\u5185\u6838\u53d1 SIGCHLD \u7ed9\u7236\u8fdb\u7a0b
    \n\/\/ \u5982\u679c\u4e0d\u5904\u7406，\u5b50\u8fdb\u7a0b\u4f1a\u53d8\u6210"\u50f5\u5c38"（\u5360\u7528\u7cfb\u7edf PID \u540d\u989d）
    \nvoid sigchld_handler(int sig) {
    \n \/\/ waitpid：\u56de\u6536\u6240\u6709\u5df2\u9000\u51fa\u7684\u5b50\u8fdb\u7a0b
    \n \/\/ -1 \u8868\u793a"\u56de\u6536\u4efb\u610f\u5b50\u8fdb\u7a0b"，WNOHANG \u8868\u793a"\u4e0d\u963b\u585e，\u6ca1\u6b7b\u5c31\u8fd4\u56de"
    \n while (waitpid(-1, NULL, WNOHANG) > 0);
    \n}<\/p>\n

    int main() {
    \n int server_fd, client_fd;
    \n struct sockaddr_in server_addr, client_addr;
    \n socklen_t client_len = sizeof(client_addr);
    \n char buffer[BUFFER_SIZE];<\/p>\n

    \/\/ \u2460 \u6ce8\u518c\u4fe1\u53f7\u5904\u7406\u2014\u2014\u5c31\u50cf\u7ed9\u7236\u8fdb\u7a0b\u88c5\u4e86\u4e2a"\u5b50\u8fdb\u7a0b\u53bb\u4e16\u901a\u77e5\u94c3"
    \n signal(SIGCHLD, sigchld_handler);<\/p>\n

    \/\/ \u2461 \u521b\u5efa\u5957\u63a5\u5b57（socket：\u5728\u7cfb\u7edf\u4e2d\u5360\u4e00\u4e2a"\u7535\u8bdd\u53f7\u7801"）
    \n server_fd = socket(AF_INET, SOCK_STREAM, 0);
    \n \/\/ AF_INET：\u4f7f\u7528 IPv4
    \n \/\/ SOCK_STREAM：\u4f7f\u7528 TCP（\u53ef\u9760\u3001\u6709\u8fde\u63a5）
    \n \/\/ 0：\u534f\u8bae\u81ea\u52a8\u9009\u62e9（TCP \u5c31\u662f IPPROTO_TCP）<\/p>\n

    \/\/ \u2462 \u8bbe\u7f6e\u7aef\u53e3\u590d\u7528\u2014\u2014\u9632\u6b62\u91cd\u542f\u65f6 "Address already in use" \u62a5\u9519
    \n int opt = 1;
    \n setsockopt(server_fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));<\/p>\n

    \/\/ \u2463 \u914d\u7f6e\u670d\u52a1\u5668\u5730\u5740（\u8eab\u4efd\u8bc1\u4fe1\u606f）
    \n memset(&server_addr, 0, sizeof(server_addr)); \/\/ \u5148\u6e05\u96f6，\u9632\u6b62\u5783\u573e\u6570\u636e
    \n server_addr.sin_family = AF_INET; \/\/ \u5730\u5740\u5bb6\u65cf：IPv4
    \n server_addr.sin_port = htons(PORT); \/\/ \u7aef\u53e3\u53f7，htons \u628a\u5b57\u8282\u5e8f\u8f6c\u6210\u7f51\u7edc\u5e8f
    \n server_addr.sin_addr.s_addr = INADDR_ANY; \/\/ \u76d1\u542c\u672c\u673a\u6240\u6709\u7f51\u5361（0.0.0.0）<\/p>\n

    \/\/ \u2464 \u7ed1\u5b9a\u2014\u2014\u628a"\u7535\u8bdd\u53f7\u7801"\u548c"\u8eab\u4efd\u8bc1"\u7ed1\u5728\u4e00\u8d77
    \n bind(server_fd, (struct sockaddr *)&server_addr, sizeof(server_addr));<\/p>\n

    \/\/ \u2465 \u5f00\u59cb\u76d1\u542c\u2014\u2014\u50cf\u9910\u5385\u6253\u5f00\u95e8\u5f00\u59cb\u8fce\u5ba2，5 \u662f\u6392\u961f\u4e0a\u9650
    \n listen(server_fd, 5);
    \n printf("\u591a\u8fdb\u7a0b\u670d\u52a1\u5668\u542f\u52a8，PID=%d，\u76d1\u542c\u7aef\u53e3 %d\\\\n", getpid(), PORT);<\/p>\n

    \/\/ \u2466 \u4e3b\u5faa\u73af：\u4e0d\u505c\u63a5\u5ba2，\u6bcf\u63a5\u4e00\u4f4d\u5c31\u558a\u4e00\u4e2a\u65b0\u67dc\u5458（fork）
    \n while (1) {
    \n client_fd = accept(server_fd,
    \n (struct sockaddr *)&client_addr,
    \n &client_len);
    \n if (client_fd < 0) {
    \n perror("accept"); \/\/ \u6253\u5370\u9519\u8bef\u539f\u56e0
    \n continue; \/\/ \u51fa\u9519\u4e5f\u522b\u5d29\u6e83，\u7ee7\u7eed\u7b49\u4e0b\u4e00\u4f4d
    \n }<\/p>\n

    pid_t pid = fork();
    \n if (pid == 0) {
    \n \/\/ ========== \u5b50\u8fdb\u7a0b：\u6211\u5c31\u662f\u65b0\u67dc\u5458 ==========
    \n close(server_fd); \/\/ \u5b50\u8fdb\u7a0b\u4e0d\u8fce\u5ba2，\u5173\u6389\u76d1\u542c\u5957\u63a5\u5b57<\/p>\n

    printf("\u5b50\u8fdb\u7a0b %d \u5f00\u59cb\u670d\u52a1 %s:%d\\\\n",
    \n getpid(),
    \n inet_ntoa(client_addr.sin_addr), \/\/ IP \u5730\u5740
    \n ntohs(client_addr.sin_port)); \/\/ \u7aef\u53e3\u53f7<\/p>\n

    \/\/ Echo：\u6536\u5230\u4ec0\u4e48\u5c31\u56de\u4ec0\u4e48（\u50cf\u590d\u8bfb\u673a）
    \n int n;
    \n while ((n = read(client_fd, buffer, sizeof(buffer) – 1)) > 0) {
    \n buffer[n] = '\\\\0'; \/\/ \u624b\u52a8\u52a0\u5b57\u7b26\u4e32\u7ed3\u5c3e
    \n printf("\u5b50\u8fdb\u7a0b %d \u6536\u5230: %s", getpid(), buffer);
    \n write(client_fd, buffer, n); \/\/ \u539f\u6837\u53d1\u56de
    \n }<\/p>\n

    close(client_fd);
    \n printf("\u5b50\u8fdb\u7a0b %d \u4e0b\u73ed\\\\n", getpid());
    \n exit(0); \/\/ \u5b50\u8fdb\u7a0b\u4efb\u52a1\u5b8c\u6210，\u4f18\u96c5\u9000\u51fa<\/p>\n

    } else if (pid > 0) {
    \n \/\/ ========== \u7236\u8fdb\u7a0b：\u8fce\u5bbe\u5458\u7ee7\u7eed\u8fce\u5ba2 ==========
    \n close(client_fd); \/\/ \u7236\u8fdb\u7a0b\u4e0d\u670d\u52a1\u5ba2\u6237，\u5173\u6389\u5ba2\u6237\u5957\u63a5\u5b57
    \n \/\/ \u7ee7\u7eed\u5faa\u73af，\u7b49\u4e0b\u4e00\u4f4d<\/p>\n

    } else {
    \n perror("fork"); \/\/ fork \u5931\u8d25（\u6bd4\u5982\u7cfb\u7edf\u8fdb\u7a0b\u6570\u6ee1\u4e86）
    \n close(client_fd);
    \n }
    \n }<\/p>\n

    close(server_fd);
    \n return 0;
    \n}<\/p>\n

    \u7b2c 5 \u6b65 \u2192\u00a0\u7f16\u8bd1\u8fd0\u884c：<\/p>\n

    # \u7f16\u8bd1（\u591a\u7ebf\u7a0b\u7248\u672c\u9700\u8981 -lpthread，\u591a\u8fdb\u7a0b\u4e0d\u9700\u8981\u989d\u5916\u94fe\u63a5\u5e93）
    \ngcc -Wall -g fork_server.c -o fork_server<\/p>\n

    # \u8fd0\u884c
    \n.\/fork_server<\/p>\n

    \u770b\u5230\u8f93\u51fa\u00a0\u591a\u8fdb\u7a0b\u670d\u52a1\u5668\u542f\u52a8，PID=xxxxx，\u76d1\u542c\u7aef\u53e3 8080\u00a0\u5c31\u8bf4\u660e\u6210\u529f\u3002<\/p>\n

    \u7b2c 6 \u6b65 \u2192\u00a0\u6d4b\u8bd5：\u5728\u53e6\u4e00\u4e2a\u7ec8\u7aef\u7528 telnet \u8fde\u63a5：<\/p>\n

    # \u53e6\u5f00\u4e00\u4e2a\u7ec8\u7aef
    \ntelnet 127.0.0.1 8080<\/p>\n

    # \u8f93\u5165\u4efb\u610f\u6587\u5b57，\u56de\u8f66，\u670d\u52a1\u5668\u4f1a\u539f\u6837\u8fd4\u56de
    \nhello # \u4f60\u4f1a\u770b\u5230\u670d\u52a1\u5668\u56de\u663e "hello"<\/p>\n

    \u518d\u5f00\u7b2c3\u4e2a\u7ec8\u7aef\u91cd\u590d\u4e0a\u8ff0\u64cd\u4f5c\u2014\u2014\u4f60\u4f1a\u53d1\u73b0\u6bcf\u4e2a\u5ba2\u6237\u7aef\u90fd\u88ab\u72ec\u7acb\u670d\u52a1，\u4e92\u4e0d\u5f71\u54cd\u3002<\/p>\n

    2.4 \u591a\u8fdb\u7a0b\u6a21\u578b\u5173\u952e\u70b9\u901f\u67e5<\/h4>\n\n\n\n\n\n\n\n
    \u5173\u952e\u70b9<\/td>\n\u4e3a\u4ec0\u4e48\u5fc5\u987b\u8fd9\u6837\u505a<\/td>\n\u4e0d\u505a\u7684\u540e\u679c<\/td>\n<\/tr>\n
    \u6ce8\u518c\u00a0SIGCHLD\u00a0\u4fe1\u53f7<\/td>\n\u5b50\u8fdb\u7a0b\u9000\u51fa\u65f6\u901a\u77e5\u7236\u8fdb\u7a0b\u56de\u6536<\/td>\n\u50f5\u5c38\u8fdb\u7a0b\u5806\u79ef，ps aux\u00a0\u663e\u793a\u5927\u91cf\u00a0<defunct><\/td>\n<\/tr>\n
    \u7236\u8fdb\u7a0b\u00a0close(client_fd)<\/td>\n\u5b50\u8fdb\u7a0b\u00a0fork\u00a0\u540e\u590d\u5236\u4e86\u6587\u4ef6\u63cf\u8ff0\u7b26，\u7236\u8fdb\u7a0b\u4e0d\u5173\u4f1a\u5bfc\u81f4\u5f15\u7528\u8ba1\u6570 > 1<\/td>\n\u5b50\u8fdb\u7a0b\u9000\u51fa\u540e\u8fde\u63a5\u53ef\u80fd\u65e0\u6cd5\u5b8c\u5168\u91ca\u653e<\/td>\n<\/tr>\n
    \u5b50\u8fdb\u7a0b\u00a0close(server_fd)<\/td>\n\u5b50\u8fdb\u7a0b\u4e0d\u9700\u8981\u76d1\u542c\u65b0\u8fde\u63a5<\/td>\n\u8d44\u6e90\u6cc4\u6f0f，\u4e14\u53ef\u80fd\u5e72\u6270\u7236\u8fdb\u7a0b<\/td>\n<\/tr>\n
    \u8d44\u6e90\u5f00\u9500\u8ba4\u77e5<\/td>\n\u6bcf\u4e2a\u5ba2\u6237\u7aef = \u4e00\u4e2a\u72ec\u7acb\u8fdb\u7a0b（\u5185\u5b58\u3001\u9875\u8868\u3001PID）<\/td>\n\u51e0\u767e\u4e2a\u5ba2\u6237\u7aef\u53ef\u80fd\u5c31\u6491\u4e0d\u4f4f\u4e86<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

    \u26a0\ufe0f\u00a0\u9884\u8b66：\u5982\u679c\u4f60\u5fd8\u4e86\u6ce8\u518c\u00a0SIGCHLD，\u8fd0\u884c\u4e00\u6bb5\u65f6\u95f4\u540e\u00a0ps aux | grep fork_server\u00a0\u4f1a\u53d1\u73b0\u4e00\u5806\u00a0<defunct>\u00a0\u50f5\u5c38\u8fdb\u7a0b\u3002\u5b83\u4eec\u5360\u7740 PID \u4e0d\u653e，\u6700\u7ec8\u53ef\u80fd\u5bfc\u81f4\u7cfb\u7edf\u65e0\u6cd5\u521b\u5efa\u65b0\u8fdb\u7a0b\u3002<\/p>\n

    \n

    \u7b2c\u4e09\u90e8\u5206：\u591a\u7ebf\u7a0b\u5e76\u53d1\u670d\u52a1\u5668（Pthread \u6a21\u578b）<\/h3>\n

    3.1 \u6838\u5fc3\u601d\u60f3\u2014\u2014\u4e00\u5f20\u56fe\u770b\u61c2<\/h4>\n

    \u4e3b\u7ebf\u7a0b（\u8fce\u5bbe\u5458）
    \n \u2502
    \n \u251c\u2500\u2500 accept() \u2190 \u6765\u5ba2\u4eba\u4e86！
    \n \u2502
    \n \u251c\u2500\u2500 pthread_create() \u2192 \u7ebf\u7a0bA（\u5206\u8eabA）\u2192 \u670d\u52a1\u5ba2\u6237A \u2192 \u9000\u51fa
    \n \u2502
    \n \u251c\u2500\u2500 accept() \u2190 \u53c8\u6765\u4e00\u4e2a！
    \n \u2502
    \n \u251c\u2500\u2500 pthread_create() \u2192 \u7ebf\u7a0bB（\u5206\u8eabB）\u2192 \u670d\u52a1\u5ba2\u6237B \u2192 \u9000\u51fa
    \n …<\/p>\n

    \u901a\u4fd7\u7c7b\u6bd4：\u7ebf\u7a0b\u5c31\u50cf"\u5206\u8eab\u672f"\u3002\u4f60\u4e0d\u662f\u96c7\u65b0\u5458\u5de5，\u800c\u662f\u628a\u81ea\u5df1\u590d\u5236\u51fa\u4e00\u4efd"\u6295\u5f71"，\u6bcf\u4e2a\u6295\u5f71\u53bb\u670d\u52a1\u4e00\u4e2a\u5ba2\u4eba\u3002\u56e0\u4e3a\u8fd9\u4e9b\u6295\u5f71\u5171\u4eab\u540c\u4e00\u4e2a\u5927\u8111（\u5185\u5b58\u7a7a\u95f4），\u6240\u4ee5\u521b\u5efa\u5feb\u3001\u5207\u6362\u5feb，\u4f46\u4e00\u65e6\u6709\u4e00\u4e2a\u6295\u5f71\u6454\u5012\u4e86（\u5d29\u6e83），\u6240\u6709\u4eba\u90fd\u5f97\u8ddf\u7740\u5012\u3002<\/p>\n

    3.2 \u7f16\u5199\u4ee3\u7801<\/h4>\n

    \u7b2c 1 \u6b65 \u2192\u00a0\u521b\u5efa\u00a0thread_server.c：<\/p>\n

    vim thread_server.c<\/p>\n

    \u7b2c 2 \u6b65 \u2192\u00a0\u8f93\u5165\u5b8c\u6574\u4ee3\u7801：<\/p>\n

    #include <stdio.h>
    \n#include <stdlib.h>
    \n#include <string.h>
    \n#include <unistd.h>
    \n#include <sys\/socket.h>
    \n#include <netinet\/in.h>
    \n#include <arpa\/inet.h>
    \n#include <pthread.h> \/\/ \u591a\u7ebf\u7a0b\u9700\u8981\u8fd9\u4e2a\u5934\u6587\u4ef6<\/p>\n

    #define PORT 8080
    \n#define BUFFER_SIZE 1024<\/p>\n

    \/\/ \u7ebf\u7a0b\u51fd\u6570：\u6bcf\u4e2a\u7ebf\u7a0b\u90fd\u5728\u8fd9\u4e2a\u51fd\u6570\u91cc\u670d\u52a1\u81ea\u5df1\u7684\u5ba2\u6237
    \n\/\/ \u53c2\u6570 arg \u662f\u4e00\u4e2a\u6307\u5411 int \u7684\u6307\u9488（\u5ba2\u6237\u7aef\u7684\u6587\u4ef6\u63cf\u8ff0\u7b26）
    \nvoid* client_handler(void *arg) {
    \n int client_fd = *(int*)arg; \/\/ \u5148\u628a\u53c2\u6570\u89e3\u51fa\u6765
    \n free(arg); \/\/ \u7528\u5b8c\u7acb\u523b\u91ca\u653e，\u9632\u6b62\u5185\u5b58\u6cc4\u6f0f！
    \n char buffer[BUFFER_SIZE];
    \n int n;<\/p>\n

    \/\/ \u6253\u5370\u7ebf\u7a0b ID（\u7528 pthread_self() \u83b7\u53d6）
    \n printf("\u7ebf\u7a0b %lu \u5f00\u59cb\u670d\u52a1\\\\n", pthread_self());<\/p>\n

    \/\/ Echo \u5faa\u73af：\u8bfb\u5230\u5c31\u56de
    \n while ((n = read(client_fd, buffer, sizeof(buffer) – 1)) > 0) {
    \n buffer[n] = '\\\\0';
    \n printf("\u7ebf\u7a0b %lu \u6536\u5230: %s", pthread_self(), buffer);
    \n write(client_fd, buffer, n);
    \n }<\/p>\n

    close(client_fd);
    \n printf("\u7ebf\u7a0b %lu \u4e0b\u73ed\\\\n", pthread_self());
    \n return NULL;
    \n}<\/p>\n

    int main() {
    \n int server_fd, *client_fd_ptr; \/\/ \u26a0\ufe0f \u6ce8\u610f：client_fd_ptr \u662f\u6307\u9488，\u4e0d\u662f\u666e\u901a int
    \n struct sockaddr_in server_addr, client_addr;
    \n socklen_t client_len = sizeof(client_addr);
    \n pthread_t tid;<\/p>\n

    \/\/ \u521b\u5efa\u5957\u63a5\u5b57\u3001\u8bbe\u7f6e\u7aef\u53e3\u590d\u7528
    \n server_fd = socket(AF_INET, SOCK_STREAM, 0);
    \n int opt = 1;
    \n setsockopt(server_fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));<\/p>\n

    \/\/ \u914d\u7f6e\u670d\u52a1\u5668\u5730\u5740
    \n memset(&server_addr, 0, sizeof(server_addr));
    \n server_addr.sin_family = AF_INET;
    \n server_addr.sin_port = htons(PORT);
    \n server_addr.sin_addr.s_addr = INADDR_ANY;<\/p>\n

    \/\/ \u7ed1\u5b9a + \u76d1\u542c
    \n bind(server_fd, (struct sockaddr *)&server_addr, sizeof(server_addr));
    \n listen(server_fd, 5);
    \n printf("\u591a\u7ebf\u7a0b\u670d\u52a1\u5668\u542f\u52a8，\u76d1\u542c\u7aef\u53e3 %d\\\\n", PORT);<\/p>\n

    \/\/ \u4e3b\u5faa\u73af
    \n while (1) {
    \n \/\/ \u26a0\ufe0f \u5173\u952e：\u5fc5\u987b\u5728\u5806\u4e0a\u5206\u914d\u5185\u5b58，\u4e0d\u80fd\u4f20\u6808\u4e0a\u53d8\u91cf！
    \n \/\/ \u539f\u56e0：\u5982\u679c\u4f20 &client_fd（\u6808\u53d8\u91cf），\u4e0b\u4e00\u6b21 accept \u4f1a\u8986\u76d6\u5b83\u7684\u503c
    \n \/\/ \u7ebf\u7a0b\u53ef\u80fd\u8bfb\u5230\u9519\u8bef\u7684\u6570\u636e
    \n client_fd_ptr = malloc(sizeof(int));
    \n *client_fd_ptr = accept(server_fd,
    \n (struct sockaddr *)&client_addr,
    \n &client_len);<\/p>\n

    if (*client_fd_ptr < 0) {
    \n perror("accept");
    \n free(client_fd_ptr); \/\/ \u51fa\u9519\u4e5f\u522b\u5fd8\u91ca\u653e
    \n continue;
    \n }<\/p>\n

    printf("\u65b0\u5ba2\u6237\u7aef %s:%d \u8fde\u63a5\\\\n",
    \n inet_ntoa(client_addr.sin_addr),
    \n ntohs(client_addr.sin_port));<\/p>\n

    \/\/ \u521b\u5efa\u7ebf\u7a0b\u53bb\u670d\u52a1
    \n \/\/ \u53c2\u6570\u8bf4\u660e：&tid=\u7ebf\u7a0bID\u8f93\u51fa, NULL=\u9ed8\u8ba4\u5c5e\u6027,
    \n \/\/ client_handler=\u7ebf\u7a0b\u51fd\u6570, client_fd_ptr=\u4f20\u7ed9\u7ebf\u7a0b\u7684\u53c2\u6570
    \n pthread_create(&tid, NULL, client_handler, client_fd_ptr);<\/p>\n

    \/\/ \u5206\u79bb\u7ebf\u7a0b：\u544a\u8bc9\u7cfb\u7edf"\u4e0d\u7528\u7b49\u6211，\u6211\u7ed3\u675f\u540e\u81ea\u52a8\u56de\u6536"
    \n \/\/ \u8fd9\u6837\u4e3b\u7ebf\u7a0b\u4e0d\u9700\u8981\u8c03\u7528 pthread_join \u963b\u585e\u7b49\u5f85
    \n pthread_detach(tid);
    \n }<\/p>\n

    close(server_fd);
    \n return 0;
    \n}<\/p>\n

    \u7b2c 3 \u6b65 \u2192\u00a0\u7f16\u8bd1\u8fd0\u884c（\u6ce8\u610f\u8981\u52a0\u00a0-lpthread）：<\/p>\n

    # \u7f16\u8bd1\u2014\u2014pthread \u4e0d\u662f\u6807\u51c6 C \u5e93\u7684\u4e00\u90e8\u5206，\u5fc5\u987b\u663e\u5f0f\u94fe\u63a5
    \ngcc -Wall -g thread_server.c -o thread_server -lpthread<\/p>\n

    # \u8fd0\u884c
    \n.\/thread_server<\/p>\n

    \u26a0\ufe0f\u00a0\u6700\u5bb9\u6613\u72af\u7684\u9519：\u7f16\u8bd1\u65f6\u5fd8\u4e86\u00a0-lpthread，\u94fe\u63a5\u9636\u6bb5\u62a5\u4e00\u5806\u00a0undefined reference to pthread_create\u3002\u52a0\u4e0a\u5c31\u597d\u4e86\u3002<\/p>\n

    \u7b2c 4 \u6b65 \u2192\u00a0\u6d4b\u8bd5：\u540c\u6837\u7528 telnet：<\/p>\n

    # \u7ec8\u7aef2
    \ntelnet 127.0.0.1 8080<\/p>\n

    # \u7ec8\u7aef3
    \ntelnet 127.0.0.1 8080<\/p>\n

    3.3 \u591a\u7ebf\u7a0b\u6a21\u578b\u5173\u952e\u70b9\u901f\u67e5<\/h4>\n\n\n\n\n\n\n\n
    \u5173\u952e\u70b9<\/td>\n\u4e3a\u4ec0\u4e48\u5fc5\u987b\u8fd9\u6837\u505a<\/td>\n\u4e0d\u505a\u7684\u540e\u679c<\/td>\n<\/tr>\n
    \u53c2\u6570\u7528\u00a0malloc\u00a0\u5806\u5206\u914d<\/td>\n\u6808\u53d8\u91cf\u5728\u5faa\u73af\u4e2d\u4f1a\u88ab\u8986\u76d6，\u7ebf\u7a0b\u8bfb\u5230\u7684\u53ef\u80fd\u662f\u4e0b\u4e2a\u5ba2\u6237\u7aef\u7684 fd<\/td>\n\u4e24\u4e2a\u7ebf\u7a0b\u670d\u52a1\u540c\u4e00\u4e2a\u5ba2\u6237\u7aef，\u6570\u636e\u4e71\u5957<\/td>\n<\/tr>\n
    pthread_detach<\/td>\n\u4e3b\u7ebf\u7a0b\u4e0d\u963b\u585e\u7b49\u5b50\u7ebf\u7a0b\u7ed3\u675f<\/td>\n\u5982\u679c\u4e0d join \u4e5f\u4e0d detach，\u7ebf\u7a0b\u8d44\u6e90\u6c38\u8fdc\u4e0d\u4f1a\u56de\u6536（\u5185\u5b58\u6cc4\u6f0f）<\/td>\n<\/tr>\n
    \u5171\u4eab\u6570\u636e\u52a0\u9501<\/td>\n\u591a\u7ebf\u7a0b\u540c\u65f6\u5199\u5168\u5c40\u53d8\u91cf\u4f1a\u53d1\u751f\u7ade\u4e89<\/td>\n\u8ba1\u6570\u5668\u9519\u4e71\u3001\u94fe\u8868\u65ad\u94fe，\u4e14\u6781\u96be\u590d\u73b0\u8c03\u8bd5<\/td>\n<\/tr>\n
    \u5d29\u6e83\u4f20\u64ad<\/td>\n\u4e00\u4e2a\u7ebf\u7a0b\u6bb5\u9519\u8bef = \u6574\u4e2a\u8fdb\u7a0b\u6b7b<\/td>\n\u4e0d\u50cf\u591a\u8fdb\u7a0b\u90a3\u6837\u80fd\u9694\u79bb\u6545\u969c<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

    \u26a0\ufe0f\u00a0\u9884\u8b66：\u5982\u679c\u4f60\u7528\u00a0malloc\u00a0\u5206\u914d\u4e86\u00a0client_fd_ptr\u00a0\u4f46\u5fd8\u4e86\u5728\u7ebf\u7a0b\u51fd\u6570\u91cc\u00a0free(arg)，\u6bcf\u8fde\u63a5\u4e00\u4e2a\u5ba2\u6237\u7aef\u5c31\u6cc4\u6f0f 4 \u5b57\u8282（\u6216 8 \u5b57\u8282）\u3002\u770b\u4e0a\u53bb\u5f88\u5c0f，\u8dd1\u4e00\u5929\u4e0b\u6765\u53ef\u80fd\u6cc4\u6f0f\u51e0\u767e MB\u3002<\/p>\n

    \n

    \u7b2c\u56db\u90e8\u5206：\u591a\u8fdb\u7a0b vs \u591a\u7ebf\u7a0b \u2014\u2014 \u7ec8\u6781\u5bf9\u51b3<\/h3>\n\n\n\n\n\n\n\n\n\n\n\n
    \u7ef4\u5ea6<\/td>\n\u591a\u8fdb\u7a0b（Fork）<\/td>\n\u591a\u7ebf\u7a0b（Pthread）<\/td>\n<\/tr>\n
    \u521b\u5efa\u5f00\u9500<\/td>\n\u9ad8（\u590d\u5236\u9875\u8868\u3001\u6587\u4ef6\u63cf\u8ff0\u7b26\u8868\u7b49）<\/td>\n\u4f4e（\u53ea\u9700\u65b0\u5efa\u6808\u548c\u5bc4\u5b58\u5668）<\/td>\n<\/tr>\n
    \u5207\u6362\u5f00\u9500<\/td>\n\u9ad8（\u5207\u6362\u9875\u8868，TLB \u5237\u65b0）<\/td>\n\u4f4e（\u53ea\u5207\u6362\u5bc4\u5b58\u5668\u4e0a\u4e0b\u6587）<\/td>\n<\/tr>\n
    \u5185\u5b58\u5360\u7528<\/td>\n\u9ad8（\u72ec\u7acb\u5730\u5740\u7a7a\u95f4）<\/td>\n\u4f4e（\u5171\u4eab\u5730\u5740\u7a7a\u95f4）<\/td>\n<\/tr>\n
    \u901a\u4fe1\u65b9\u5f0f<\/td>\n\u9700\u8981 IPC（\u7ba1\u9053\u3001\u5171\u4eab\u5185\u5b58\u3001\u6d88\u606f\u961f\u5217）<\/td>\n\u76f4\u63a5\u8bfb\u5199\u5168\u5c40\u53d8\u91cf（\u4f46\u8981\u52a0\u9501）<\/td>\n<\/tr>\n
    \u6570\u636e\u9694\u79bb\/\u5b89\u5168\u6027<\/td>\n\u6781\u9ad8（\u4e00\u4e2a\u5d29\u4e86\u4e0d\u5f71\u54cd\u5176\u4ed6）<\/td>\n\u6781\u4f4e（\u4e00\u4e2a\u5d29\u4e86\u5168\u6302）<\/td>\n<\/tr>\n
    \u6700\u5927\u5e76\u53d1\u6570<\/td>\n\u901a\u5e38\u51e0\u767e~\u51e0\u5343（\u53d7 PID \u548c\u5185\u5b58\u9650\u5236）<\/td>\n\u53ef\u8fbe\u6570\u4e07（\u53d7\u5185\u5b58\u9650\u5236）<\/td>\n<\/tr>\n
    \u7f16\u7a0b\u96be\u5ea6<\/td>\n\u8f83\u4f4e（\u4fe1\u53f7\u5904\u7406\u7a0d\u9ebb\u70e6）<\/td>\n\u8f83\u9ad8（\u9501\u3001\u6b7b\u9501\u3001\u6761\u4ef6\u53d8\u91cf）<\/td>\n<\/tr>\n
    \u73b0\u5b9e\u4e16\u754c\u8c01\u5728\u7528<\/td>\nApache Prefork\u3001Chrome \u591a\u8fdb\u7a0b\u67b6\u6784<\/td>\nNginx\u3001MySQL \u8fde\u63a5\u6c60\u3001Java \u7ebf\u7a0b\u6c60<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

    \u9009\u578b\u53e3\u8bc0<\/h4>\n
      \n
    • \u6c42\u7a33（\u94f6\u884c\/\u5de5\u63a7\/\u5173\u952e\u4e1a\u52a1）\u2192 \u591a\u8fdb\u7a0b\u3002\u6302\u4e86\u53ef\u4ee5\u91cd\u542f，\u4e0d\u5f71\u54cd\u5176\u4ed6\u3002<\/li>\n
    • \u6c42\u5feb（Web \u670d\u52a1\u5668\/\u6e38\u620f\u670d\u52a1\u5668\/API \u7f51\u5173）\u2192 \u591a\u7ebf\u7a0b\u3002\u80fd\u652f\u6491\u66f4\u9ad8\u5e76\u53d1\u3002<\/li>\n
    • \u4e24\u5168\u5176\u7f8e（\u73b0\u4ee3\u4e3b\u6d41）\u2192 IO \u590d\u7528（epoll）+ \u5c11\u91cf\u7ebf\u7a0b\u6c60\u3002\u8be6\u89c1\u7b2c\u4e94\u90e8\u5206\u3002<\/li>\n<\/ul>\n
      \n

      \u7b2c\u4e94\u90e8\u5206：IO \u590d\u7528\u6280\u672f \u2014\u2014 \u4e00\u4e2a\u670d\u52a1\u5458\u641e\u5b9a\u5168\u573a<\/h3>\n

      5.0 \u963b\u585e\u548c\u975e\u963b\u585e\u7684\u5c40\u9650<\/h4>\n

      \u5728\u8bb2 IO \u590d\u7528\u4e4b\u524d，\u6211\u4eec\u5148\u641e\u6e05\u695a\u4e24\u4e2a\u6982\u5ff5：<\/p>\n

      \u963b\u585e I\/O（Blocking I\/O）\u2014\u2014\u9ed8\u8ba4\u6a21\u5f0f：<\/p>\n

      read(fd, buf, size); \/\/ fd \u6ca1\u6570\u636e？\u8fdb\u7a0b\u5c31"\u7761\u7740"，\u76f4\u5230\u6709\u6570\u636e\u624d\u9192<\/p>\n

      \u901a\u4fd7\u7c7b\u6bd4：\u6253\u7535\u8bdd\u65f6\u5bf9\u65b9\u4e0d\u8bf4\u8bdd，\u4f60\u5c31\u5728\u90a3\u5934\u7b49\u7740，\u4e0d\u6302\u7535\u8bdd（\u8fdb\u7a0b\u6302\u8d77），\u5f53\u7136\u4e5f\u4e0d\u80fd\u63a5\u522b\u4eba\u7684\u7535\u8bdd\u3002<\/p>\n

      \u975e\u963b\u585e I\/O（Non-blocking I\/O）\u2014\u2014\u624b\u52a8\u8bbe\u7f6e\u540e：<\/p>\n

      int flags = fcntl(fd, F_GETFL, 0);
      \nfcntl(fd, F_SETFL, flags | O_NONBLOCK); \/\/ \u8bbe\u4e3a\u975e\u963b\u585e<\/p>\n

      int n = read(fd, buf, size); \/\/ \u6ca1\u6570\u636e？\u7acb\u523b\u8fd4\u56de -1，errno=EAGAIN<\/p>\n

      \u901a\u4fd7\u7c7b\u6bd4：\u4f60\u6bcf\u9694\u4e00\u79d2\u770b\u4e00\u773c\u5bf9\u65b9\u6709\u6ca1\u6709\u8bf4\u8bdd，\u6ca1\u8bf4\u5c31\u626d\u5934\u770b\u4e00\u773c\u522b\u4eba\u3002\u4f46\u5982\u679c\u7528\u00a0for\u00a0\u5faa\u73af\u75af\u72c2\u53bb\u68c0\u67e5（\u8f6e\u8be2），CPU \u4f1a\u98d9\u5230 100%，\u5927\u90e8\u5206\u65f6\u95f4\u90fd\u5728\u505a\u65e0\u7528\u529f\u2014\u2014\u8fd9\u53eb"\u5fd9\u7b49\u5f85"\u3002<\/p>\n

      IO \u590d\u7528\u7684\u89e3\u51b3\u601d\u8def：\u522b\u81ea\u5df1\u6328\u4e2a\u95ee\u4e86，\u8ba9\u5185\u6838\u5e2e\u4f60\u76ef\u7740！\u4f60\u53ea\u9700\u8981\u544a\u8bc9\u5185\u6838"\u5e2e\u6211\u76ef\u7740\u8fd9 100 \u4e2a\u6587\u4ef6\u63cf\u8ff0\u7b26，\u8c01\u6709\u6570\u636e\u4e86\u53eb\u9192\u6211"\u3002\u8fd9\u6837\u4f60\u53ea\u9700\u8981\u963b\u585e\u5728\u4e00\u4e2a\u5730\u65b9（\u6bd4\u5982\u00a0epoll_wait），\u800c\u4e0d\u662f\u5728 100 \u4e2a\u00a0read\u00a0\u4e4b\u95f4\u75b2\u4e8e\u5954\u547d\u3002<\/p>\n

      \u4e00\u53e5\u8bdd\u603b\u7ed3：IO \u590d\u7528\u5c31\u662f"\u7528\u4e00\u4e2a\u963b\u585e，\u6362\u6389 100 \u4e2a\u963b\u585e"\u3002<\/p>\n

      \n

      5.1 \u4e09\u5144\u5f1f\u767b\u573a：select \/ poll \/ epoll<\/h4>\n

      \u65f6\u95f4\u7ebf：1983 select（\u8001\u5927\u54e5）\u2192 1997 poll（\u4e8c\u54e5）\u2192 2002 epoll（\u4e09\u5f1f，\u738b\u8005）<\/p>\n\n\n\n\n\n\n\n\n\n\n
      <\/td>\nselect<\/td>\npoll<\/td>\nepoll<\/td>\n<\/tr>\n
      \u5e74\u4ee3<\/td>\n1983 (BSD)<\/td>\n1997 (SVR4)<\/td>\n2002 (Linux 2.5.44)<\/td>\n<\/tr>\n
      \u539f\u7406<\/td>\n\u5185\u6838\u8f6e\u8be2\u6240\u6709 fd<\/td>\n\u5185\u6838\u8f6e\u8be2\u6240\u6709 fd<\/td>\n\u4e8b\u4ef6\u9a71\u52a8，\u5185\u6838\u4e3b\u52a8\u901a\u77e5<\/td>\n<\/tr>\n
      fd \u6570\u91cf\u9650\u5236<\/td>\n\u786c\u9650\u5236 FD_SETSIZE（\u9ed8\u8ba4 1024）<\/td>\n\u65e0\u786c\u9650\u5236<\/td>\n\u65e0\u786c\u9650\u5236<\/td>\n<\/tr>\n
      \u6570\u636e\u7ed3\u6784<\/td>\n3 \u4e2a\u4f4d\u56fe（fd_set）<\/td>\n\u52a8\u6001\u6570\u7ec4（struct pollfd[]）<\/td>\n\u7ea2\u9ed1\u6811 + \u5c31\u7eea\u94fe\u8868<\/td>\n<\/tr>\n
      \u6bcf\u6b21\u8c03\u7528\u662f\u5426\u91cd\u65b0\u4f20\u5165 fd \u5217\u8868<\/td>\n\u662f（\u4ece\u7528\u6237\u6001\u62f7\u8d1d\u5230\u5185\u6838\u6001）<\/td>\n\u662f（\u4ece\u7528\u6237\u6001\u62f7\u8d1d\u5230\u5185\u6838\u6001）<\/td>\n\u5426（fd \u6ce8\u518c\u5728\u5185\u6838，\u957f\u671f\u6709\u6548）<\/td>\n<\/tr>\n
      \u590d\u6742\u5ea6<\/td>\nO(n) \u2014\u2014 n \u4e3a\u6700\u5927 fd \u503c<\/td>\nO(n) \u2014\u2014 n \u4e3a fd \u603b\u6570<\/td>\nO(1)\u00a0\u2014\u2014 \u53ea\u904d\u5386\u5c31\u7eea\u7684 fd<\/td>\n<\/tr>\n
      \u9002\u7528\u573a\u666f<\/td>\n\u5c11\u91cf fd，\u8de8\u5e73\u53f0<\/td>\n\u4e2d\u7b49\u91cf fd<\/td>\n\u5927\u89c4\u6a21\u5e76\u53d1（C10K+），Linux \u4e13\u5c5e<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

      \u4e00\u53e5\u8bdd\u603b\u7ed3：select \u548c poll \u662f"\u6328\u4e2a\u70b9\u540d"，epoll \u662f"\u8c01\u4e3e\u624b\u53eb\u8c01"\u3002<\/p>\n

      \n

      5.2 select \u2014\u2014 \u8001\u5927\u54e5\u7684\u7b28\u529e\u6cd5<\/h4>\n

      5.2.1 \u6838\u5fc3 API<\/h5>\n

      #include <sys\/select.h><\/p>\n

      int select(int nfds, \/\/ \u6700\u5927 fd \u503c + 1
      \n fd_set *readfds, \/\/ \u60f3\u76d1\u63a7"\u53ef\u8bfb"\u7684 fd \u96c6\u5408
      \n fd_set *writefds, \/\/ \u60f3\u76d1\u63a7"\u53ef\u5199"\u7684 fd \u96c6\u5408
      \n fd_set *exceptfds, \/\/ \u60f3\u76d1\u63a7"\u5f02\u5e38"\u7684 fd \u96c6\u5408
      \n struct timeval *timeout); \/\/ \u8d85\u65f6\u65f6\u95f4<\/p>\n

      \/\/ \u64cd\u4f5c fd_set \u7684\u5b8f
      \nFD_ZERO(fd_set *set); \/\/ \u6e05\u7a7a\u96c6\u5408
      \nFD_SET(int fd, fd_set *set); \/\/ \u628a fd \u52a0\u5165\u96c6\u5408
      \nFD_CLR(int fd, fd_set *set); \/\/ \u628a fd \u4ece\u96c6\u5408\u79fb\u9664
      \nFD_ISSET(int fd, fd_set *set); \/\/ \u68c0\u67e5 fd \u662f\u5426\u5728\u96c6\u5408\u4e2d（\u5373\u662f\u5426\u5c31\u7eea）<\/p>\n

      5.2.2 \u5de5\u4f5c\u6d41\u7a0b<\/h5>\n

      \u7b2c 1 \u6b65：\u628a\u6240\u6709\u60f3\u76d1\u63a7\u7684 fd \u585e\u8fdb fd_set
      \n\u7b2c 2 \u6b65：\u8c03\u7528 select()，\u8fdb\u7a0b\u963b\u585e，\u5185\u6838\u53bb\u8f6e\u8be2\u6240\u6709 fd
      \n\u7b2c 3 \u6b65：\u6709 fd \u5c31\u7eea \u2192 select \u8fd4\u56de，\u5185\u6838\u4fee\u6539 fd_set（\u53ea\u7559\u4e0b\u5c31\u7eea\u7684 fd）
      \n\u7b2c 4 \u6b65：\u904d\u5386\u6240\u6709 fd，\u7528 FD_ISSET \u6570\u54ea\u4e9b\u5c31\u7eea\u4e86
      \n\u7b2c 5 \u6b65：\u5904\u7406\u5c31\u7eea\u7684 fd，\u56de\u5230\u7b2c 1 \u6b65<\/p>\n

      \u901a\u4fd7\u7c7b\u6bd4：select \u5c31\u50cf\u4e00\u4e2a\u8001\u5e08，\u6bcf\u5929\u65e9\u6668\u628a\u5168\u73ed 200 \u4e2a\u5b66\u751f\u540d\u5355\u6284\u4e00\u904d\u4ea4\u4e0a\u53bb\u3002\u4e0a\u8bfe\u65f6\u60f3\u77e5\u9053\u8c01\u4e3e\u624b\u2014\u2014\u4ed6\u6328\u4e2a\u70b9\u540d："\u5f20\u4e09\u4e3e\u624b\u4e86\u5417？\u674e\u56db\u4e3e\u624b\u4e86\u5417？…" \u6bcf\u5929\u8fd8\u8981\u628a 200 \u4eba\u540d\u5355\u91cd\u65b0\u6284\u4e00\u904d\u3002\u4eba\u5c11\u8fd8\u884c，\u4eba\u591a\u4e86\u6548\u7387\u5947\u4f4e\u3002<\/p>\n

      5.2.3 \u5b8c\u6574\u4ee3\u7801：select_server.c<\/h5>\n

      \u7b2c 1 \u6b65 \u2192\u00a0\u521b\u5efa\u6587\u4ef6：<\/p>\n

      vim select_server.c<\/p>\n

      \u7b2c 2 \u6b65 \u2192\u00a0\u8f93\u5165\u4ee3\u7801：<\/p>\n

      #include <stdio.h>
      \n#include <stdlib.h>
      \n#include <string.h>
      \n#include <unistd.h>
      \n#include <sys\/socket.h>
      \n#include <netinet\/in.h>
      \n#include <arpa\/inet.h>
      \n#include <sys\/select.h> \/\/ select \u9700\u8981\u8fd9\u4e2a\u5934\u6587\u4ef6<\/p>\n

      #define PORT 8080
      \n#define BUFFER_SIZE 1024
      \n#define MAX_CLIENTS 1024 \/\/ FD_SETSIZE \u9ed8\u8ba4\u5c31\u662f 1024<\/p>\n

      int main() {
      \n int server_fd, client_fd, max_fd;
      \n struct sockaddr_in server_addr, client_addr;
      \n socklen_t client_len = sizeof(client_addr);
      \n char buffer[BUFFER_SIZE];<\/p>\n

      \/\/ \u5b58\u50a8\u6240\u6709\u5ba2\u6237\u7aef fd，\u65b9\u4fbf\u904d\u5386（\u5f25\u8865 select \u7684\u4e0d\u8db3）
      \n int client_fds[MAX_CLIENTS];
      \n for (int i = 0; i < MAX_CLIENTS; i++) client_fds[i] = -1; \/\/ -1 \u8868\u793a\u7a7a\u4f4d<\/p>\n

      \/\/ \u2460 \u521b\u5efa\u5957\u63a5\u5b57
      \n server_fd = socket(AF_INET, SOCK_STREAM, 0);
      \n int opt = 1;
      \n setsockopt(server_fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));<\/p>\n

      \/\/ \u2461 \u7ed1\u5b9a + \u76d1\u542c
      \n memset(&server_addr, 0, sizeof(server_addr));
      \n server_addr.sin_family = AF_INET;
      \n server_addr.sin_port = htons(PORT);
      \n server_addr.sin_addr.s_addr = INADDR_ANY;
      \n bind(server_fd, (struct sockaddr *)&server_addr, sizeof(server_addr));
      \n listen(server_fd, 5);<\/p>\n

      printf("select \u670d\u52a1\u5668\u542f\u52a8，\u76d1\u542c\u7aef\u53e3 %d\\\\n", PORT);
      \n printf("\u6700\u5927\u652f\u6301 %d \u4e2a\u5ba2\u6237\u7aef（\u786c\u9650\u5236）\\\\n", MAX_CLIENTS);<\/p>\n

      while (1) {
      \n fd_set read_fds; \/\/ \u6bcf\u6b21\u5faa\u73af\u91cd\u65b0\u521b\u5efa\u96c6\u5408
      \n FD_ZERO(&read_fds); \/\/ \u6e05\u7a7a
      \n FD_SET(server_fd, &read_fds); \/\/ \u628a server_fd \u52a0\u5165\u76d1\u63a7\u5217\u8868
      \n max_fd = server_fd; \/\/ \u8bb0\u5f55\u6700\u5927 fd \u503c<\/p>\n

      \/\/ \u2461 \u628a\u6240\u6709\u5ba2\u6237\u7aef fd \u52a0\u5165\u76d1\u63a7\u96c6\u5408
      \n for (int i = 0; i < MAX_CLIENTS; i++) {
      \n if (client_fds[i] != -1) {
      \n FD_SET(client_fds[i], &read_fds);
      \n if (client_fds[i] > max_fd) max_fd = client_fds[i];
      \n }
      \n }<\/p>\n

      \/\/ \u2462 \u8c03\u7528 select \u2014 \u5185\u6838\u5e2e\u4f60\u76ef\u7740\u6240\u6709 fd
      \n \/\/ \u53c2\u6570：max_fd+1（\u6700\u5927 fd \u7f16\u53f7+1）\u3001\u8bfb\u96c6\u5408\u3001\u5199\u96c6\u5408（NULL=\u4e0d\u76d1\u63a7）\u3001
      \n \/\/ \u5f02\u5e38\u96c6\u5408（NULL=\u4e0d\u76d1\u63a7）\u3001\u8d85\u65f6（NULL=\u6c38\u8fdc\u7b49）
      \n int ready = select(max_fd + 1, &read_fds, NULL, NULL, NULL);
      \n if (ready < 0) {
      \n perror("select");
      \n continue;
      \n }<\/p>\n

      \/\/ \u2463 \u68c0\u67e5 server_fd \u662f\u5426\u6709\u65b0\u8fde\u63a5
      \n if (FD_ISSET(server_fd, &read_fds)) {
      \n client_fd = accept(server_fd,
      \n (struct sockaddr *)&client_addr,
      \n &client_len);
      \n if (client_fd >= 0) {
      \n printf("\u65b0\u5ba2\u6237\u7aef %s:%d \u8fde\u63a5，fd=%d\\\\n",
      \n inet_ntoa(client_addr.sin_addr),
      \n ntohs(client_addr.sin_port), client_fd);<\/p>\n

      \/\/ \u627e\u4e2a\u7a7a\u4f4d\u5b58\u8d77\u6765
      \n for (int i = 0; i < MAX_CLIENTS; i++) {
      \n if (client_fds[i] == -1) {
      \n client_fds[i] = client_fd;
      \n break;
      \n }
      \n }
      \n }
      \n ready–; \/\/ \u8fd9\u4e2a\u4e8b\u4ef6\u5904\u7406\u5b8c\u4e86
      \n }<\/p>\n

      \/\/ \u2464 \u904d\u5386\u68c0\u67e5\u6bcf\u4e2a\u5ba2\u6237\u7aef\u662f\u5426\u6709\u6570\u636e
      \n for (int i = 0; i < MAX_CLIENTS && ready > 0; i++) {
      \n int fd = client_fds[i];
      \n if (fd == -1) continue;<\/p>\n

      if (FD_ISSET(fd, &read_fds)) {
      \n int n = read(fd, buffer, sizeof(buffer) – 1);<\/p>\n

      if (n <= 0) {
      \n \/\/ \u5ba2\u6237\u7aef\u65ad\u5f00\u8fde\u63a5（read \u8fd4\u56de 0）\u6216\u51fa\u9519（\u8fd4\u56de -1）
      \n if (n == 0) {
      \n printf("\u5ba2\u6237\u7aef fd=%d \u65ad\u5f00\u8fde\u63a5\\\\n", fd);
      \n } else {
      \n perror("read");
      \n }
      \n close(fd);
      \n client_fds[i] = -1; \/\/ \u91ca\u653e\u4f4d\u7f6e
      \n } else {
      \n \/\/ \u6b63\u5e38\u6536\u5230\u6570\u636e，Echo \u56de\u53bb
      \n buffer[n] = '\\\\0';
      \n printf("\u5ba2\u6237\u7aef fd=%d \u53d1\u6765: %s", fd, buffer);
      \n write(fd, buffer, n);
      \n }
      \n ready–;
      \n }
      \n }
      \n }<\/p>\n

      close(server_fd);
      \n return 0;
      \n}<\/p>\n

      \u7b2c 3 \u6b65 \u2192\u00a0\u7f16\u8bd1\u8fd0\u884c：<\/p>\n

      gcc -Wall -g select_server.c -o select_server
      \n.\/select_server<\/p>\n

      5.2.4 select \u7684\u81f4\u547d\u7f3a\u9677<\/h5>\n\n\n\n\n\n\n\n
      \u7f3a\u9677<\/td>\n\u5f71\u54cd<\/td>\n<\/tr>\n
      fd \u6570\u91cf\u4e0a\u9650 = FD_SETSIZE（\u9ed8\u8ba4 1024）<\/td>\n\u6539\u8fd9\u4e2a\u503c\u9700\u8981\u91cd\u65b0\u7f16\u8bd1\u5185\u6838，\u6781\u4e0d\u53cb\u597d<\/td>\n<\/tr>\n
      \u6bcf\u6b21\u8c03\u7528\u90fd\u8981\u628a\u6574\u4e2a fd_set \u4ece\u7528\u6237\u6001\u62f7\u5230\u5185\u6838\u6001<\/td>\n\u8fde\u63a5\u6570\u591a\u65f6，\u62f7\u8d1d\u5f00\u9500\u5de8\u5927<\/td>\n<\/tr>\n
      \u5185\u6838\u904d\u5386\u6240\u6709\u00a0fd（\u4e0d\u662f\u53ea\u904d\u5386\u5c31\u7eea\u7684）<\/td>\nO(n)，1 \u4e07\u4e2a\u8fde\u63a5\u8981\u904d\u5386 1 \u4e07\u6b21<\/td>\n<\/tr>\n
      \u8fd4\u56de\u540e\u7528\u6237\u8fd8\u8981\u904d\u5386\u4e00\u6b21\u627e\u5c31\u7eea fd<\/td>\n\u53c8\u4e00\u904d O(n)<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

      select\u00a0\u7528\u4e8e\u5b66\u4e60\u7406\u89e3 IO \u590d\u7528\u539f\u7406\u5f88\u5408\u9002，\u4f46\u751f\u4ea7\u73af\u5883\u7edd\u4e0d\u8981\u7528\u5b83\u5904\u7406\u9ad8\u5e76\u53d1\u3002<\/p>\n

      \n

      5.3 poll \u2014\u2014 \u4e8c\u54e5\u7684\u5c0f\u6539\u8fdb<\/h4>\n

      5.3.1 \u6838\u5fc3 API<\/h5>\n

      #include <poll.h><\/p>\n

      struct pollfd {
      \n int fd; \/\/ \u8981\u76d1\u63a7\u7684\u6587\u4ef6\u63cf\u8ff0\u7b26
      \n short events; \/\/ \u60f3\u76d1\u63a7\u7684\u4e8b\u4ef6（POLLIN=\u53ef\u8bfb, POLLOUT=\u53ef\u5199）
      \n short revents; \/\/ \u5185\u6838\u8fd4\u56de：\u5b9e\u9645\u53d1\u751f\u7684\u4e8b\u4ef6
      \n};<\/p>\n

      int poll(struct pollfd *fds, \/\/ pollfd \u6570\u7ec4
      \n nfds_t nfds, \/\/ \u6570\u7ec4\u5143\u7d20\u4e2a\u6570
      \n int timeout); \/\/ \u8d85\u65f6（\u6beb\u79d2），-1 \u8868\u793a\u6c38\u8fdc\u7b49<\/p>\n

      5.3.2 poll \u76f8\u6bd4 select \u7684\u6539\u8fdb<\/h5>\n\n\n\n\n\n\n
      \u6539\u8fdb\u70b9<\/td>\nselect<\/td>\npoll<\/td>\n<\/tr>\n
      fd \u6570\u91cf\u4e0a\u9650<\/td>\n\u786c\u7f16\u7801 FD_SETSIZE=1024<\/td>\n\u65e0\u786c\u9650\u5236，\u53ea\u53d7\u5185\u5b58\u9650\u5236<\/td>\n<\/tr>\n
      \u6570\u636e\u7ed3\u6784<\/td>\n\u4f4d\u56fe（fd_set），\u53ea\u80fd\u7528\u5b8f\u64cd\u4f5c<\/td>\n\u7ed3\u6784\u4f53\u6570\u7ec4（pollfd），\u66f4\u76f4\u89c2<\/td>\n<\/tr>\n
      \u4e8b\u4ef6\u548c\u7ed3\u679c\u5206\u79bb<\/td>\n\u4e0d\u5206\u79bb（\u540c\u4e00\u4e2a fd_set \u6539\u6765\u6539\u53bb）<\/td>\n\u5206\u79bb：events \u662f\u4f60\u60f3\u76d1\u63a7\u7684，revents \u662f\u5185\u6838\u8fd4\u56de\u7684<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

      \u901a\u4fd7\u7c7b\u6bd4：poll \u4e0d\u518d\u7528"\u82b1\u540d\u518c"，\u6539\u7528"\u7b7e\u5230\u8868"\u3002\u6bcf\u884c\u5199\u4e00\u4e2a\u5b66\u751f\u540d\u5b57\u548c\u60f3\u8981\u5173\u6ce8\u7684\u9879\u76ee，\u8001\u5e08\u4e0d\u7528\u5168\u90e8\u91cd\u65b0\u6284\u2014\u2014\u53ef\u4ee5\u589e\u5220\u6539\u3002\u4f46\u8001\u5e08\u8fd8\u662f\u8981\u5168\u4f53\u70b9\u540d\u3002<\/p>\n

      5.3.3 \u5b8c\u6574\u4ee3\u7801：poll_server.c<\/h5>\n

      \u7b2c 1 \u6b65 \u2192\u00a0\u521b\u5efa\u6587\u4ef6：<\/p>\n

      vim poll_server.c<\/p>\n

      \u7b2c 2 \u6b65 \u2192\u00a0\u8f93\u5165\u4ee3\u7801：<\/p>\n

      #include <stdio.h>
      \n#include <stdlib.h>
      \n#include <string.h>
      \n#include <unistd.h>
      \n#include <sys\/socket.h>
      \n#include <netinet\/in.h>
      \n#include <arpa\/inet.h>
      \n#include <poll.h> \/\/ poll \u9700\u8981\u8fd9\u4e2a\u5934\u6587\u4ef6<\/p>\n

      #define PORT 8080
      \n#define BUFFER_SIZE 1024
      \n#define MAX_CLIENTS 10240 \/\/ poll \u6ca1\u6709\u786c\u9650\u5236，\u8fd9\u91cc\u8bbe\u4e00\u4e2a\u5408\u7406\u7684\u8f6f\u4e0a\u9650<\/p>\n

      int main() {
      \n int server_fd, client_fd;
      \n struct sockaddr_in server_addr, client_addr;
      \n socklen_t client_len = sizeof(client_addr);
      \n char buffer[BUFFER_SIZE];<\/p>\n

      \/\/ pollfd \u6570\u7ec4：\u5b58\u6240\u6709\u8981\u76d1\u63a7\u7684 fd
      \n struct pollfd fds[MAX_CLIENTS + 1]; \/\/ +1 \u7ed9 server_fd
      \n int nfds = 0; \/\/ \u5f53\u524d\u6570\u7ec4\u4e2d\u6709\u591a\u5c11\u4e2a\u6709\u6548\u6761\u76ee<\/p>\n

      \/\/ \u2460 \u521b\u5efa\u5957\u63a5\u5b57
      \n server_fd = socket(AF_INET, SOCK_STREAM, 0);
      \n int opt = 1;
      \n setsockopt(server_fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));<\/p>\n

      \/\/ \u2461 \u7ed1\u5b9a + \u76d1\u542c
      \n memset(&server_addr, 0, sizeof(server_addr));
      \n server_addr.sin_family = AF_INET;
      \n server_addr.sin_port = htons(PORT);
      \n server_addr.sin_addr.s_addr = INADDR_ANY;
      \n bind(server_fd, (struct sockaddr *)&server_addr, sizeof(server_addr));
      \n listen(server_fd, 5);<\/p>\n

      \/\/ \u2462 \u628a server_fd \u52a0\u5165\u76d1\u63a7\u5217\u8868
      \n fds[0].fd = server_fd;
      \n fds[0].events = POLLIN; \/\/ POLLIN \u8868\u793a"\u53ef\u8bfb"（\u65b0\u8fde\u63a5\u6216\u6570\u636e\u5230\u8fbe）
      \n nfds = 1;<\/p>\n

      printf("poll \u670d\u52a1\u5668\u542f\u52a8，\u76d1\u542c\u7aef\u53e3 %d\\\\n", PORT);<\/p>\n

      while (1) {
      \n \/\/ \u2463 \u8c03\u7528 poll：\u963b\u585e\u7b49\u5f85，\u6709\u4e8b\u4ef6\u65f6\u8fd4\u56de
      \n \/\/ timeout=-1 \u8868\u793a\u6c38\u8fdc\u7b49
      \n int ready = poll(fds, nfds, -1);
      \n if (ready < 0) {
      \n perror("poll");
      \n continue;
      \n }<\/p>\n

      \/\/ \u2464 \u904d\u5386\u68c0\u67e5\u6bcf\u4e2a fd
      \n for (int i = 0; i < nfds && ready > 0; i++) {
      \n \/\/ revents \u4e2d\u662f\u5426\u6709\u6211\u4eec\u5173\u5fc3\u7684\u4e8b\u4ef6
      \n if (fds[i].revents == 0) continue;<\/p>\n

      if (fds[i].fd == server_fd) {
      \n \/\/ ===== server_fd：\u6709\u65b0\u8fde\u63a5 =====
      \n if (fds[i].revents & POLLIN) {
      \n client_fd = accept(server_fd,
      \n (struct sockaddr *)&client_addr,
      \n &client_len);
      \n if (client_fd >= 0 && nfds < MAX_CLIENTS + 1) {
      \n printf("\u65b0\u5ba2\u6237\u7aef %s:%d \u8fde\u63a5，fd=%d\\\\n",
      \n inet_ntoa(client_addr.sin_addr),
      \n ntohs(client_addr.sin_port), client_fd);<\/p>\n

      fds[nfds].fd = client_fd;
      \n fds[nfds].events = POLLIN; \/\/ \u76d1\u63a7\u53ef\u8bfb
      \n nfds++;
      \n } else if (client_fd >= 0) {
      \n printf("\u5ba2\u6237\u7aef\u6570\u91cf\u5df2\u8fbe\u4e0a\u9650，\u62d2\u7edd\u65b0\u8fde\u63a5\\\\n");
      \n close(client_fd);
      \n }
      \n }
      \n ready–;<\/p>\n

      } else {
      \n \/\/ ===== \u5ba2\u6237\u7aef fd：\u6709\u6570\u636e\u6216\u65ad\u5f00 =====
      \n int fd = fds[i].fd;<\/p>\n

      if (fds[i].revents & POLLIN) {
      \n int n = read(fd, buffer, sizeof(buffer) – 1);<\/p>\n

      if (n <= 0) {
      \n \/\/ \u65ad\u5f00\u6216\u51fa\u9519
      \n if (n == 0) printf("\u5ba2\u6237\u7aef fd=%d \u65ad\u5f00\\\\n", fd);
      \n else perror("read");
      \n close(fd);<\/p>\n

      \/\/ \u4ece\u6570\u7ec4\u4e2d\u79fb\u9664：\u628a\u6700\u540e\u4e00\u4e2a\u5143\u7d20\u642c\u8fc7\u6765，\u7136\u540e nfds–
      \n fds[i] = fds[nfds – 1];
      \n nfds–;
      \n i–; \/\/ \u56de\u9000\u4e00\u6b65，\u56e0\u4e3a\u5f53\u524d\u4f4d\u7f6e\u73b0\u5728\u662f\u65b0\u7684\u5143\u7d20
      \n } else {
      \n buffer[n] = '\\\\0';
      \n printf("\u5ba2\u6237\u7aef fd=%d \u53d1\u6765: %s", fd, buffer);
      \n write(fd, buffer, n);
      \n }
      \n }<\/p>\n

      \/\/ \u4e5f\u53ef\u4ee5\u68c0\u67e5 POLLERR（\u8fde\u63a5\u51fa\u9519）\u548c POLLHUP（\u5ba2\u6237\u7aef\u6302\u65ad）
      \n if (fds[i].revents & (POLLERR | POLLHUP)) {
      \n printf("\u5ba2\u6237\u7aef fd=%d \u5f02\u5e38\u65ad\u5f00\\\\n", fd);
      \n close(fd);
      \n fds[i] = fds[nfds – 1];
      \n nfds–;
      \n i–;
      \n }<\/p>\n

      ready–;
      \n }
      \n }
      \n }<\/p>\n

      close(server_fd);
      \n return 0;
      \n}<\/p>\n

      \u7b2c 3 \u6b65 \u2192\u00a0\u7f16\u8bd1\u8fd0\u884c：<\/p>\n

      gcc -Wall -g poll_server.c -o poll_server
      \n.\/poll_server<\/p>\n

      5.3.4 poll \u7684\u4e0d\u8db3<\/h5>\n

      poll \u89e3\u51b3\u4e86 select \u7684"1024 \u4e0a\u9650"\u95ee\u9898，\u4f46\u904d\u5386\u6240\u6709 fd \u7684 O(n) \u95ee\u9898\u4ecd\u5728\u3002\u5f53\u4f60\u6709 1 \u4e07\u4e2a\u8fde\u63a5\u4f46\u53ea\u6709 3 \u4e2a\u6d3b\u8dc3\u65f6，poll \u4ecd\u7136\u8981\u626b\u63cf\u5168\u90e8 1 \u4e07\u4e2a\u3002\u8fd9\u5c31\u662f epoll \u8981\u89e3\u51b3\u7684\u3002<\/p>\n

      \n

      5.4 epoll \u2014\u2014 Linux \u738b\u724c\u767b\u573a<\/h4>\n

      5.4.1 \u6838\u5fc3\u601d\u60f3<\/h5>\n

      select\/poll：\u6bcf\u6b21\u8c03\u7528\u90fd\u628a"\u5168\u73ed\u540d\u5355"\u4ea4\u4e0a\u53bb，\u8001\u5e08\u8bf4"\u81ea\u5df1\u53bb\u6570\u8c01\u4e3e\u624b"
      \nepoll： \u53ea\u5728\u5b66\u671f\u521d\u767b\u8bb0\u4e00\u6b21\u3002\u4e4b\u540e\u6709\u4eba\u4e3e\u624b，\u8001\u5e08\u76f4\u63a5\u9012\u7ed9\u4f60\u4e00\u5f20
      \n "\u4e3e\u624b\u540d\u5355"\u2014\u2014\u4f60\u53ea\u9700\u8981\u5904\u7406\u540d\u5355\u4e0a\u7684\u4eba！<\/p>\n

      epoll \u7684\u4e09\u4e2a\u6838\u5fc3 API：<\/p>\n

      #include <sys\/epoll.h><\/p>\n

      \/\/ \u2460 \u521b\u5efa epoll \u5b9e\u4f8b（\u76f8\u5f53\u4e8e\u5728\u8001\u5e08\u90a3\u91cc\u6ce8\u518c\u4e00\u4e2a"\u4e3e\u624b\u76d1\u542c\u7cfb\u7edf"）
      \nint epoll_create1(int flags); \/\/ flags \u901a\u5e38\u8bbe\u4e3a 0<\/p>\n

      \/\/ \u2461 \u6ce8\u518c\/\u4fee\u6539\/\u5220\u9664\u8981\u76d1\u63a7\u7684 fd（\u76f8\u5f53\u4e8e\u628a\u5b66\u751f\u52a0\u5165\u4e3e\u624b\u76d1\u542c\u7cfb\u7edf）
      \nint epoll_ctl(int epfd, int op, int fd, struct epoll_event *event);
      \n\/\/ op: EPOLL_CTL_ADD（\u52a0\u5165）\/ EPOLL_CTL_MOD（\u4fee\u6539）\/ EPOLL_CTL_DEL（\u5220\u9664）<\/p>\n

      \/\/ \u2462 \u7b49\u5f85\u4e8b\u4ef6（\u76f8\u5f53\u4e8e\u8001\u5e08\u8bf4："\u8fd9\u662f\u4e3e\u624b\u540d\u5355，\u4f60\u5904\u7406\u5427"）
      \nint epoll_wait(int epfd, struct epoll_event *events,
      \n int maxevents, int timeout);<\/p>\n

      struct epoll_event {
      \n uint32_t events; \/\/ EPOLLIN（\u53ef\u8bfb）\/ EPOLLOUT（\u53ef\u5199）\/ EPOLLERR（\u9519\u8bef）
      \n epoll_data_t data; \/\/ \u53ef\u4ee5\u5b58 fd \u6216\u81ea\u5b9a\u4e49\u6307\u9488
      \n};<\/p>\n

      5.4.2 epoll \u4e3a\u4ec0\u4e48\u5feb？<\/h5>\n\n\n\n\n\n\n\n
      \u539f\u56e0<\/td>\n\u89e3\u91ca<\/td>\n<\/tr>\n
      \u4e8b\u4ef6\u9a71\u52a8<\/td>\n\u5c31\u7eea\u7684 fd \u4f1a\u81ea\u52a8\u6302\u5230\u5185\u6838\u7684\u5c31\u7eea\u94fe\u8868\u4e0a，epoll_wait \u53ea\u8fd4\u56de\u8fd9\u4e9b\u5c31\u7eea fd，\u4e0d\u626b\u63cf\u5168\u91cf<\/td>\n<\/tr>\n
      \u7ea2\u9ed1\u6811\u5b58\u50a8<\/td>\n\u6240\u6709\u6ce8\u518c\u7684 fd \u5b58\u5728\u7ea2\u9ed1\u6811\u4e2d，\u589e\u5220\u6539\u67e5\u90fd\u662f O(log n)<\/td>\n<\/tr>\n
      \u53ea\u62f7\u8d1d\u5c31\u7eea\u4e8b\u4ef6<\/td>\nepoll_wait \u53ea\u628a\u5c31\u7eea\u7684 fd \u4fe1\u606f\u4ece\u5185\u6838\u62f7\u5230\u7528\u6237\u6001，\u4e0d\u662f\u5168\u90e8 fd<\/td>\n<\/tr>\n
      \u957f\u671f\u6ce8\u518c<\/td>\nfd \u6ce8\u518c\u4e00\u6b21\u540e\u957f\u671f\u6709\u6548，\u4e0d\u9700\u8981\u6bcf\u6b21\u5faa\u73af\u91cd\u65b0\u4f20\u5165<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

      \u901a\u4fd7\u7c7b\u6bd4：select\/poll \u50cf\u662f\u4f60\u6bcf\u5929\u628a\u5168\u73ed\u540d\u5355\u4ea4\u7ed9\u8001\u5e08，\u8001\u5e08\u6bcf\u5929\u4ece\u5934\u6570\u4e00\u904d\u3002epoll \u50cf\u662f\u8001\u5e08\u624b\u91cc\u6709\u4e2a"\u4e3e\u624b\u94c3"\u2014\u2014\u53ea\u6709\u4e3e\u624b\u7684\u5b66\u751f（\u5c31\u7eea fd）\u624d\u4f1a\u89e6\u53d1\u94c3\u54cd，\u8001\u5e08\u76f4\u63a5\u628a\u4e3e\u624b\u540d\u5355\u7ed9\u4f60\u3002<\/p>\n

      5.4.3 \u4e24\u79cd\u89e6\u53d1\u6a21\u5f0f<\/h5>\n\n\n\n\n\n
      \u6a21\u5f0f<\/td>\n\u884c\u4e3a<\/td>\n\u9002\u7528\u573a\u666f<\/td>\n<\/tr>\n
      LT（\u6c34\u5e73\u89e6\u53d1，\u9ed8\u8ba4）<\/td>\n\u53ea\u8981\u7f13\u51b2\u533a\u6709\u6570\u636e，\u6bcf\u6b21 epoll_wait \u90fd\u4f1a\u901a\u77e5\u4f60<\/td>\n\u7b80\u5355\u53ef\u9760，\u517c\u5bb9 select\/poll \u7f16\u7a0b\u6a21\u578b，\u4e0d\u6613\u6f0f\u4e8b\u4ef6<\/td>\n<\/tr>\n
      ET（\u8fb9\u7f18\u89e6\u53d1）<\/td>\n\u53ea\u5728\u72b6\u6001\u53d8\u5316\u65f6\u901a\u77e5\u4e00\u6b21（\u4ece\u65e0\u5230\u6709）<\/td>\n\u9ad8\u6027\u80fd，\u51cf\u5c11\u91cd\u590d\u901a\u77e5，\u4f46\u8981\u6c42 fd \u5fc5\u987b\u8bbe\u4e3a\u975e\u963b\u585e，\u5426\u5219\u5bb9\u6613\u5361\u6b7b<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

      ET \u6a21\u5f0f\u901a\u4fd7\u89e3\u91ca：
      \nLT = "\u4f60\u7897\u91cc\u8fd8\u6709\u996d，\u6211\u6bcf\u6b21\u8d70\u8fc7\u90fd\u63d0\u9192\u4f60\u4e00\u4e0b"
      \nET = "\u6211\u558a\u4e00\u6b21'\u5f00\u996d\u4e86'，\u4f60\u81ea\u5df1\u8bb0\u5f97\u5403\u5230\u7897\u7a7a，\u6211\u4e0d\u4f1a\u518d\u558a"<\/p>\n

      \u26a0\ufe0f\u00a0ET \u6a21\u5f0f\u7684\u7ea2\u7ebf：\u4f7f\u7528 ET \u6a21\u5f0f\u65f6，fd \u5fc5\u987b\u662f\u975e\u963b\u585e\u7684，\u4e14\u5fc5\u987b\u5faa\u73af\u00a0read\u00a0\u76f4\u5230\u8fd4\u56de\u00a0EAGAIN（\u8868\u793a\u8bfb\u7a7a\u4e86），\u5426\u5219\u53ef\u80fd\u6f0f\u6389\u6570\u636e\u3002<\/p>\n

      5.4.4 \u5b8c\u6574\u4ee3\u7801：epoll_server.c（LT \u6a21\u5f0f，\u5373\u9ed8\u8ba4\u6a21\u5f0f，\u6700\u5b89\u5168）<\/h5>\n

      \u7b2c 1 \u6b65 \u2192\u00a0\u521b\u5efa\u6587\u4ef6：<\/p>\n

      vim epoll_server.c<\/p>\n

      \u7b2c 2 \u6b65 \u2192\u00a0\u8f93\u5165\u4ee3\u7801：<\/p>\n

      #include <stdio.h>
      \n#include <stdlib.h>
      \n#include <string.h>
      \n#include <unistd.h>
      \n#include <sys\/socket.h>
      \n#include <netinet\/in.h>
      \n#include <arpa\/inet.h>
      \n#include <sys\/epoll.h> \/\/ epoll \u9700\u8981\u8fd9\u4e2a\u5934\u6587\u4ef6<\/p>\n

      #define PORT 8080
      \n#define BUFFER_SIZE 1024
      \n#define MAX_EVENTS 10240 \/\/ \u4e00\u6b21\u6700\u591a\u5904\u7406\u8fd9\u4e48\u591a\u5c31\u7eea\u4e8b\u4ef6<\/p>\n

      int main() {
      \n int server_fd, client_fd, epfd;
      \n struct sockaddr_in server_addr, client_addr;
      \n socklen_t client_len = sizeof(client_addr);
      \n char buffer[BUFFER_SIZE];<\/p>\n

      \/\/ \u2460 \u521b\u5efa\u5957\u63a5\u5b57
      \n server_fd = socket(AF_INET, SOCK_STREAM, 0);
      \n int opt = 1;
      \n setsockopt(server_fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));<\/p>\n

      \/\/ \u2461 \u7ed1\u5b9a + \u76d1\u542c
      \n memset(&server_addr, 0, sizeof(server_addr));
      \n server_addr.sin_family = AF_INET;
      \n server_addr.sin_port = htons(PORT);
      \n server_addr.sin_addr.s_addr = INADDR_ANY;
      \n bind(server_fd, (struct sockaddr *)&server_addr, sizeof(server_addr));
      \n listen(server_fd, 5);<\/p>\n

      \/\/ \u2462 \u521b\u5efa epoll \u5b9e\u4f8b
      \n \/\/ epoll_create1(0) \u7b49\u4ef7\u4e8e\u65e7\u7248\u7684 epoll_create(\u4efb\u610f\u6b63\u6570)
      \n epfd = epoll_create1(0);
      \n if (epfd == -1) {
      \n perror("epoll_create1");
      \n exit(1);
      \n }<\/p>\n

      \/\/ \u2463 \u628a server_fd \u6ce8\u518c\u5230 epoll
      \n struct epoll_event ev, events[MAX_EVENTS];
      \n ev.events = EPOLLIN; \/\/ \u5173\u5fc3"\u53ef\u8bfb"\u4e8b\u4ef6（\u65b0\u8fde\u63a5\u5230\u6765）
      \n ev.data.fd = server_fd; \/\/ \u628a fd \u5b58\u8fdb\u53bb，\u65b9\u4fbf\u540e\u9762\u53d6\u51fa\u6765
      \n epoll_ctl(epfd, EPOLL_CTL_ADD, server_fd, &ev);<\/p>\n

      printf("epoll \u670d\u52a1\u5668\u542f\u52a8（LT \u6a21\u5f0f），\u76d1\u542c\u7aef\u53e3 %d\\\\n", PORT);<\/p>\n

      while (1) {
      \n \/\/ \u2464 epoll_wait：\u963b\u585e\u7b49\u5f85，\u6709\u4e8b\u4ef6\u65f6\u8fd4\u56de
      \n \/\/ \u53c2\u6570：epoll\u5b9e\u4f8b\u3001\u5b58\u653e\u4e8b\u4ef6\u7684\u6570\u7ec4\u3001\u6570\u7ec4\u5927\u5c0f\u3001\u8d85\u65f6（-1=\u6c38\u8fdc\u7b49）
      \n int nfds = epoll_wait(epfd, events, MAX_EVENTS, -1);
      \n if (nfds < 0) {
      \n perror("epoll_wait");
      \n continue;
      \n }<\/p>\n

      \/\/ \u2465 \u904d\u5386\u6240\u6709\u5c31\u7eea\u4e8b\u4ef6\u2014\u2014\u6ce8\u610f！\u53ea\u904d\u5386"\u5c31\u7eea"\u7684，\u4e0d\u662f\u5168\u90e8 fd
      \n for (int i = 0; i < nfds; i++) {
      \n int fd = events[i].data.fd;<\/p>\n

      if (fd == server_fd) {
      \n \/\/ ===== server_fd：\u6709\u65b0\u8fde\u63a5 =====
      \n client_fd = accept(server_fd,
      \n (struct sockaddr *)&client_addr,
      \n &client_len);
      \n if (client_fd >= 0) {
      \n printf("\u65b0\u5ba2\u6237\u7aef %s:%d \u8fde\u63a5，fd=%d\\\\n",
      \n inet_ntoa(client_addr.sin_addr),
      \n ntohs(client_addr.sin_port), client_fd);<\/p>\n

      \/\/ \u628a\u65b0\u5ba2\u6237\u7aef\u4e5f\u6ce8\u518c\u5230 epoll
      \n ev.events = EPOLLIN;
      \n ev.data.fd = client_fd;
      \n epoll_ctl(epfd, EPOLL_CTL_ADD, client_fd, &ev);
      \n }<\/p>\n

      } else {
      \n \/\/ ===== \u5ba2\u6237\u7aef fd：\u6709\u6570\u636e\u6216\u65ad\u5f00 =====
      \n int n = read(fd, buffer, sizeof(buffer) – 1);<\/p>\n

      if (n <= 0) {
      \n \/\/ \u65ad\u5f00\u6216\u51fa\u9519\u2014\u2014\u4ece epoll \u4e2d\u79fb\u9664\u8fd9\u4e2a fd
      \n if (n == 0) {
      \n printf("\u5ba2\u6237\u7aef fd=%d \u65ad\u5f00\u8fde\u63a5\\\\n", fd);
      \n } else {
      \n perror("read");
      \n }
      \n epoll_ctl(epfd, EPOLL_CTL_DEL, fd, NULL); \/\/ \u4ece epoll \u79fb\u9664
      \n close(fd);
      \n } else {
      \n \/\/ \u6536\u5230\u6570\u636e，\u539f\u6837\u53d1\u56de
      \n buffer[n] = '\\\\0';
      \n printf("\u5ba2\u6237\u7aef fd=%d \u53d1\u6765: %s", fd, buffer);
      \n write(fd, buffer, n);
      \n }
      \n }
      \n }
      \n }<\/p>\n

      close(server_fd);
      \n close(epfd); \/\/ \u5173\u95ed epoll \u5b9e\u4f8b
      \n return 0;
      \n}<\/p>\n

      \u7b2c 3 \u6b65 \u2192\u00a0\u7f16\u8bd1\u8fd0\u884c：<\/p>\n

      gcc -Wall -g epoll_server.c -o epoll_server
      \n.\/epoll_server<\/p>\n

      5.4.5 ET \u6a21\u5f0f\u7248\u672c（\u8fdb\u9636）<\/h5>\n

      \u5982\u679c\u4f60\u60f3\u4f53\u9a8c ET \u6a21\u5f0f\u7684\u9ad8\u6027\u80fd（\u4ee5\u53ca\u5b83\u5e26\u6765\u7684\u590d\u6742\u5ea6），\u5c06\u4e0a\u8ff0\u4ee3\u7801\u4e2d\u7684\u6838\u5fc3\u90e8\u5206\u6539\u4e3a：<\/p>\n

      \/\/ \u2460 \u8bbe\u7f6e server_fd \u548c\u6240\u6709 client_fd \u4e3a\u975e\u963b\u585e
      \nint set_nonblocking(int fd) {
      \n int flags = fcntl(fd, F_GETFL, 0);
      \n return fcntl(fd, F_SETFL, flags | O_NONBLOCK);
      \n}
      \nset_nonblocking(server_fd);<\/p>\n

      \/\/ \u2461 \u6ce8\u518c\u65f6\u52a0\u4e0a EPOLLET \u6807\u5fd7
      \nev.events = EPOLLIN | EPOLLET; \/\/ \u8fb9\u7f18\u89e6\u53d1\u6a21\u5f0f
      \nev.data.fd = server_fd;
      \nepoll_ctl(epfd, EPOLL_CTL_ADD, server_fd, &ev);<\/p>\n

      \/\/ \u2462 \u8bfb\u53d6\u6570\u636e\u65f6\u5fc5\u987b\u5faa\u73af\u8bfb\u5230 EAGAIN
      \nwhile (1) {
      \n n = read(fd, buffer, sizeof(buffer) – 1);
      \n if (n == -1) {
      \n if (errno == EAGAIN || errno == EWOULDBLOCK) {
      \n break; \/\/ \u8bfb\u5b8c\u4e86，\u6ca1\u6709\u66f4\u591a\u6570\u636e
      \n }
      \n perror("read");
      \n break;
      \n }
      \n if (n == 0) {
      \n \/\/ \u5ba2\u6237\u7aef\u5173\u95ed
      \n epoll_ctl(epfd, EPOLL_CTL_DEL, fd, NULL);
      \n close(fd);
      \n break;
      \n }
      \n buffer[n] = '\\\\0';
      \n write(fd, buffer, n);
      \n}<\/p>\n

      \u26a0\ufe0f\u00a0ET \u6a21\u5f0f\u8b66\u544a：\u4e0d\u8bbe\u975e\u963b\u585e + \u4e0d\u5faa\u73af read \u5230 EAGAIN \u2192 \u6570\u636e\u53ef\u80fd\u6c38\u8fdc\u4e22\u5931\u3002\u521d\u5b66\u8005\u5efa\u8bae\u5148\u7528 LT \u6a21\u5f0f\u8dd1\u901a，\u518d\u5c1d\u8bd5 ET\u3002<\/p>\n

      \n

      5.5 \u4e09\u5144\u5f1f\u7ec8\u6781\u5bf9\u51b3 \u2014\u2014 \u4e00\u8868\u5b9a\u4e7e\u5764<\/h4>\n\n\n\n\n\n\n\n\n\n\n\n
      \u7ef4\u5ea6<\/td>\nselect<\/td>\npoll<\/td>\nepoll<\/td>\n<\/tr>\n
      fd \u4e0a\u9650<\/td>\nFD_SETSIZE（\u901a\u5e38 1024），\u6539\u5b83\u8981\u91cd\u7f16\u8bd1\u5185\u6838<\/td>\n\u65e0\u786c\u9650\u5236，\u53d7\u5185\u5b58\u9650\u5236<\/td>\n\u65e0\u786c\u9650\u5236，\u53d7\u5185\u5b58\u9650\u5236<\/td>\n<\/tr>\n
      \u6bcf\u6b21\u8c03\u7528\u662f\u5426\u91cd\u4f20 fd \u5217\u8868<\/td>\n\u662f（\u62f7\u8d1d\u6574\u4e2a fd_set）<\/td>\n\u662f（\u62f7\u8d1d\u6574\u4e2a pollfd \u6570\u7ec4）<\/td>\n\u5426（fd \u6ce8\u518c\u5728\u5185\u6838\u7a7a\u95f4，\u4e00\u6b21\u6ce8\u518c\u957f\u671f\u6709\u6548）<\/td>\n<\/tr>\n
      \u5185\u6838\u884c\u4e3a<\/td>\n\u904d\u5386\u5168\u90e8 fd \u627e\u5230\u5c31\u7eea\u7684<\/td>\n\u904d\u5386\u5168\u90e8 fd \u627e\u5230\u5c31\u7eea\u7684<\/td>\n\u4e8b\u4ef6\u9a71\u52a8：fd \u5c31\u7eea\u65f6\u81ea\u52a8\u6302\u5230\u5c31\u7eea\u94fe\u8868<\/td>\n<\/tr>\n
      \u590d\u6742\u5ea6<\/td>\nO(n)，n = \u6700\u5927 fd \u503c<\/td>\nO(n)，n = fd \u603b\u6570<\/td>\nO(1)，\u53ea\u5173\u6ce8\u5c31\u7eea fd \u6570\u91cf<\/td>\n<\/tr>\n
      \u8fd4\u56de\u540e\u7684\u5de5\u4f5c\u91cf<\/td>\n\u904d\u5386\u6240\u6709 fd \u7528 FD_ISSET \u68c0\u67e5<\/td>\n\u904d\u5386\u6240\u6709 fd \u68c0\u67e5 revents<\/td>\n\u53ea\u904d\u5386\u8fd4\u56de\u7684\u5c31\u7eea\u4e8b\u4ef6（epoll_wait \u8fd4\u56de\u7684 nfds \u4e2a）<\/td>\n<\/tr>\n
      \u8de8\u5e73\u53f0<\/td>\n\u662f（POSIX，\u5168\u5e73\u53f0）<\/td>\n\u662f（POSIX，\u5168\u5e73\u53f0）<\/td>\n\u5426（Linux \u4e13\u5c5e\u3002BSD \u6709 kqueue，Windows \u6709 IOCP）<\/td>\n<\/tr>\n
      C10K \u95ee\u9898<\/td>\n\u65e0\u6cd5\u652f\u6491<\/td>\n\u52c9\u5f3a\u652f\u6491\u4f46\u6548\u7387\u4f4e<\/td>\n\u8f7b\u677e\u5e94\u5bf9（Nginx \u5355\u673a\u767e\u4e07\u8fde\u63a5\u9760\u7684\u5c31\u662f epoll）<\/td>\n<\/tr>\n
      \u9002\u7528\u573a\u666f<\/td>\n\u5b66\u4e60\u539f\u7406\u3001\u5c11\u91cf fd\u3001\u8de8\u5e73\u53f0\u9700\u6c42<\/td>\n\u4e2d\u5c0f\u89c4\u6a21\u3001\u8de8\u5e73\u53f0\u9700\u6c42<\/td>\n\u9ad8\u5e76\u53d1\u751f\u4ea7\u73af\u5883\u3001Linux \u670d\u52a1\u5668<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

      📌\u00a0\u672f\u8bed\u901f\u67e5：C10K \u95ee\u9898（1999 \u5e74\u63d0\u51fa）\u2014\u2014\u5373"\u5982\u4f55\u5728\u4e00\u53f0\u670d\u52a1\u5668\u4e0a\u540c\u65f6\u670d\u52a1 1 \u4e07\u4e2a\u5ba2\u6237\u7aef"\u3002epoll \u662f Linux \u7ed9\u51fa\u7684\u6807\u51c6\u7b54\u6848\u3002\u73b0\u4ee3\u5df2\u8fdb\u5316\u5230\u00a0C10M（\u5343\u4e07\u7ea7）\u3002<\/p>\n

      \n

      5.6 epoll \u5b9e\u6218：\u538b\u6d4b\u5bf9\u6bd4<\/h4>\n

      \u6211\u4eec\u6765\u76f4\u89c2\u611f\u53d7\u4e00\u4e0b\u4e09\u79cd\u6a21\u578b\u7684\u5dee\u8ddd\u3002<\/p>\n

      \u7b2c 1 \u6b65 \u2192\u00a0\u5206\u522b\u542f\u52a8\u4e09\u4e2a\u670d\u52a1\u5668（\u6bcf\u4e2a\u5728\u5355\u72ec\u7684\u7ec8\u7aef）：<\/p>\n

      # \u7ec8\u7aef1
      \n.\/select_server<\/p>\n

      # \u7ec8\u7aef2
      \n.\/poll_server<\/p>\n

      # \u7ec8\u7aef3
      \n.\/epoll_server<\/p>\n

      \u7b2c 2 \u6b65 \u2192\u00a0\u67e5\u770b CPU \u548c\u5185\u5b58\u5360\u7528（\u5f53\u8fde\u63a5\u6570\u589e\u591a\u65f6）：<\/p>\n

      # \u65b0\u5f00\u7ec8\u7aef，\u7528 top \u6216 htop \u89c2\u5bdf
      \ntop -p $(pgrep -d',' select_server)
      \ntop -p $(pgrep -d',' poll_server)
      \ntop -p $(pgrep -d',' epoll_server)<\/p>\n

      \u73b0\u8c61：\u5f53\u6709 1000 \u4e2a\u7a7a\u95f2\u8fde\u63a5（\u8fde\u63a5\u4e86\u4f46\u4e0d\u53d1\u6570\u636e）\u65f6：<\/p>\n

        \n
      • select\/poll \u6bcf\u6b21\u00a0select()\/poll()\u00a0\u8c03\u7528\u90fd\u4f1a\u904d\u5386 1000 \u4e2a fd，CPU \u4f7f\u7528\u7387\u660e\u663e\u4e0a\u5347\u3002<\/li>\n
      • epoll \u53ea\u8fd4\u56de\u5c31\u7eea\u7684 fd \u6570（\u53ef\u80fd\u662f 0），CPU \u51e0\u4e4e\u4e0d\u6da8\u3002<\/li>\n<\/ul>\n
        \n

        \u7b2c\u516d\u90e8\u5206：\u5b9e\u6218\u5bf9\u6bd4 \u2014\u2014 \u7528 telnet \u540c\u65f6\u8fde\u63a5\u591a\u4e2a\u670d\u52a1\u5668<\/h3>\n

        6.1 \u6a21\u62df\u591a\u4e2a\u5ba2\u6237\u7aef<\/h4>\n

        \u5728\u591a\u4e2a\u7ec8\u7aef\u4e2d\u540c\u65f6\u8fd0\u884c\u5ba2\u6237\u7aef：<\/p>\n

        # \u7ec8\u7aef1
        \ntelnet 127.0.0.1 8080<\/p>\n

        # \u7ec8\u7aef2
        \ntelnet 127.0.0.1 8080<\/p>\n

        # \u7ec8\u7aef3
        \ntelnet 127.0.0.1 8080<\/p>\n

        6.2 \u67e5\u770b\u8fdb\u7a0b\/\u7ebf\u7a0b\/fd \u6570\u91cf\u53d8\u5316<\/h4>\n

        # \u67e5\u770b\u591a\u8fdb\u7a0b\u670d\u52a1\u5668\u7684\u5b50\u8fdb\u7a0b
        \nps aux | grep fork_server<\/p>\n

        # \u67e5\u770b\u591a\u7ebf\u7a0b\u670d\u52a1\u5668\u7684\u7ebf\u7a0b\u6570（-T \u663e\u793a\u7ebf\u7a0b，-p PID \u6307\u5b9a\u8fdb\u7a0b）
        \nps -T -p $(pgrep thread_server)<\/p>\n

        # \u67e5\u770b epoll \u670d\u52a1\u5668\u6253\u5f00\u7684\u6587\u4ef6\u63cf\u8ff0\u7b26
        \nls -la \/proc\/$(pgrep epoll_server)\/fd | wc -l<\/p>\n

        6.3 \u7528 Python \u811a\u672c\u6a21\u62df\u5927\u91cf\u8fde\u63a5<\/h4>\n

        \u4ee5\u4e0b\u811a\u672c\u53ef\u4ee5\u5feb\u901f\u521b\u5efa 500 \u4e2a\u8fde\u63a5\u6765\u6d4b\u8bd5\u4f60\u7684\u670d\u52a1\u5668：<\/p>\n

        # \u4fdd\u5b58\u4e3a test_client.py，\u8fd0\u884c：python3 test_client.py
        \nimport socket
        \nimport time<\/p>\n

        sockets = []
        \nfor i in range(500):
        \n try:
        \n s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        \n s.connect(('127.0.0.1', 8080))
        \n s.send(f"Hello from client {i}\\\\n".encode())
        \n sockets.append(s)
        \n print(f"Client {i} connected")
        \n except Exception as e:
        \n print(f"Client {i} failed: {e}")
        \n break<\/p>\n

        print(f"Total connected: {len(sockets)}")
        \nprint("Press Ctrl+C to disconnect all…")
        \ntime.sleep(60) # \u4fdd\u6301\u8fde\u63a5 60 \u79d2<\/p>\n

        \n

        \u7b2c\u4e03\u90e8\u5206：\u907f\u5751\u6307\u5357（\u9762\u8bd5\/\u5b9e\u6218\u9ad8\u9891）<\/h3>\n\n\n\n\n\n\n\n\n\n\n\n
        \u5751<\/td>\n\u73b0\u8c61<\/td>\n\u89e3\u51b3\u65b9\u6848<\/td>\n<\/tr>\n
        \u8fdb\u7a0b\u6a21\u578b\u50f5\u5c38\u6cdb\u6ee5<\/td>\nps aux\u00a0\u770b\u5230\u5927\u91cf\u00a0<defunct><\/td>\n\u6ce8\u518c\u00a0SIGCHLD\u00a0+\u00a0waitpid\u00a0\u5faa\u73af\u56de\u6536；\u6216\u00a0signal(SIGCHLD, SIG_IGN)<\/td>\n<\/tr>\n
        \u7ebf\u7a0b\u6a21\u578b\u53c2\u6570\u4f20\u9012\u9519\u8bef<\/td>\n\u4e24\u4e2a\u7ebf\u7a0b\u670d\u52a1\u540c\u4e00\u4e2a fd<\/td>\n\u53c2\u6570\u5fc5\u987b\u5728\u5806\u4e0a\u00a0malloc，\u4e0d\u80fd\u7528\u6808\u53d8\u91cf\u5730\u5740<\/td>\n<\/tr>\n
        \u7ebf\u7a0b\u5fd8\u8bb0 detach\/join<\/td>\n\u5185\u5b58\u6301\u7eed\u589e\u957f<\/td>\n\u521b\u5efa\u540e\u7528\u00a0pthread_detach，\u6216\u5728\u7ebf\u7a0b\u5185\u00a0pthread_detach(pthread_self())<\/td>\n<\/tr>\n
        select fd \u8d85\u9650<\/td>\n\u8fde\u63a5\u6570\u8d85\u8fc7 1024 \u540e\u62d2\u7edd\u65b0\u8fde\u63a5<\/td>\n\u6362\u6210 poll \u6216 epoll<\/td>\n<\/tr>\n
        epoll ET \u6a21\u5f0f\u5361\u6b7b<\/td>\nread\u00a0\u8fd4\u56de\u540e\u7a0b\u5e8f\u4e0d\u518d\u54cd\u5e94<\/td>\nET \u5fc5\u987b\u914d\u5408\u975e\u963b\u585e fd + \u5faa\u73af read \u5230 EAGAIN<\/td>\n<\/tr>\n
        select \u6bcf\u6b21\u91cd\u8bbe fd_set<\/td>\n\u7a0b\u5e8f\u884c\u4e3a\u5f02\u5e38，\u67d0\u4e9b fd "\u4e22\u4e86"<\/td>\n\u6bcf\u6b21\u5faa\u73af\u5fc5\u987b\u00a0FD_ZERO\u00a0+ \u91cd\u65b0\u00a0FD_SET（select \u4f1a\u4fee\u6539 fd_set）<\/td>\n<\/tr>\n
        epoll_ctl \u5fd8\u8bb0 EPOLL_CTL_DEL<\/td>\n\u5173\u95ed fd \u540e epoll \u4ecd\u62a5\u544a\u4e8b\u4ef6<\/td>\n\u5173\u95ed fd \u524d\u5148\u00a0epoll_ctl(epfd, EPOLL_CTL_DEL, fd, NULL)<\/td>\n<\/tr>\n
        \u975e\u963b\u585e read \u8bef\u5224 EAGAIN<\/td>\n\u7a0b\u5e8f\u9891\u7e41\u62a5\u9519\u9000\u51fa<\/td>\nEAGAIN\/EWOULDBLOCK \u662f\u6b63\u5e38\u72b6\u6001，\u4e0d\u662f\u9519\u8bef，\u5e94\u00a0continue\u00a0\u7b49\u5f85<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
        \n

        \u603b\u7ed3<\/h3>\n

        \u8fd9\u4e24\u5929\u6211\u4eec\u8de8\u8d8a\u4e86\u5355\u7528\u6237\u670d\u52a1\u7684\u85e9\u7bf1，\u6b63\u5f0f\u8fdb\u5165\u4e86\u9ad8\u5e76\u53d1\u7f51\u7edc\u7f16\u7a0b\u7684\u4e16\u754c：<\/p>\n\n\n\n\n\n\n\n\n
        \u6280\u672f<\/td>\n\u6838\u5fc3\u601d\u8def<\/td>\n\u4e00\u53e5\u8bdd\u603b\u7ed3<\/td>\n<\/tr>\n
        \u591a\u8fdb\u7a0b（fork）<\/td>\n\u6bcf\u4e2a\u5ba2\u6237 = \u4e00\u4e2a\u5b50\u8fdb\u7a0b<\/td>\n\u7a33\u5982\u6cf0\u5c71，\u4f46\u625b\u4e0d\u4f4f\u6d77\u91cf\u8fde\u63a5<\/td>\n<\/tr>\n
        \u591a\u7ebf\u7a0b（pthread）<\/td>\n\u6bcf\u4e2a\u5ba2\u6237 = \u4e00\u4e2a\u7ebf\u7a0b<\/td>\n\u8f7b\u91cf\u5feb\u901f，\u4f46\u4e00\u635f\u4ff1\u635f<\/td>\n<\/tr>\n
        select<\/td>\n\u5185\u6838\u8f6e\u8be2 + \u4f4d\u56fe<\/td>\n\u7ecf\u5178\u5165\u95e8，\u4e0a\u9650 1024，\u904d\u5386\u5168\u91cf<\/td>\n<\/tr>\n
        poll<\/td>\n\u5185\u6838\u8f6e\u8be2 + \u52a8\u6001\u6570\u7ec4<\/td>\n\u53bb\u6389 1024 \u9650\u5236，\u4f46\u904d\u5386\u5168\u91cf\u95ee\u9898\u4ecd\u5728<\/td>\n<\/tr>\n
        epoll<\/td>\n\u4e8b\u4ef6\u9a71\u52a8 + \u7ea2\u9ed1\u6811 + \u5c31\u7eea\u94fe\u8868<\/td>\nLinux \u738b\u8005，\u53ea\u5173\u6ce8\u5c31\u7eea\u4e8b\u4ef6，O(1) \u6548\u7387<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

        \u6280\u672f\u6f14\u8fdb\u8def\u7ebf\u56fe<\/h4>\n

        \u5355\u7ebf\u7a0b\u963b\u585e\u670d\u52a1\u5668（\u6392\u961f\u6a21\u5f0f）
        \n \u2502
        \n \u251c\u2500\u2500\u2192 \u591a\u8fdb\u7a0b（fork）\u2500\u2500\u2192 \u7ebf\u7a0b\u6c60（\u9884\u521b\u5efa\u7ebf\u7a0b\u590d\u7528）
        \n \u2502
        \n \u251c\u2500\u2500\u2192 \u591a\u7ebf\u7a0b（pthread）\u2500\u2500\u2192 \u7ebf\u7a0b\u6c60 + \u4efb\u52a1\u961f\u5217
        \n \u2502
        \n \u2514\u2500\u2500\u2192 IO \u590d\u7528 \u2500\u2500\u2192 select（1983）
        \n \u2502
        \n \u2514\u2500\u2500\u2192 poll（1997）
        \n \u2502
        \n \u2514\u2500\u2500\u2192 epoll（2002）\u2500\u2500\u2192 \u73b0\u4ee3\u9ad8\u6027\u80fd\u670d\u52a1\u5668\u6807\u914d
        \n \u2502
        \n \u2514\u2500\u2500\u2192 Reactor \u6a21\u5f0f
        \n \u2514\u2500\u2500\u2192 Proactor \u6a21\u5f0f<\/p>\n

        \u73b0\u5b9e\u4e16\u754c：Nginx \u7528 epoll + \u5c11\u91cf worker \u8fdb\u7a0b，\u5355\u673a\u8f7b\u677e\u767e\u4e07\u5e76\u53d1\u3002Redis \u7528 epoll \u5b9e\u73b0\u5355\u7ebf\u7a0b\u5904\u7406\u6570\u4e07\u5ba2\u6237\u7aef\u3002\u4f60\u4eca\u5929\u5199\u7684 epoll_server \u5c31\u662f\u8fd9\u4e9b\u9876\u7ea7\u5f00\u6e90\u9879\u76ee\u7684"\u79cd\u5b50"\u3002<\/p>\n

        \n

        \u5e38\u89c1\u95ee\u9898\u901f\u67e5\u8868（Day 24-25）<\/h3>\n\n\n\n\n\n\n\n\n\n\n\n\n
        \u95ee\u9898\u73b0\u8c61<\/td>\n\u539f\u56e0<\/td>\n\u89e3\u51b3\u529e\u6cd5<\/td>\n<\/tr>\n
        fork_server\u00a0\u8fd0\u884c\u4e00\u6bb5\u65f6\u95f4\u540e\u00a0ps aux\u00a0\u51fa\u73b0\u5927\u91cf\u00a0<defunct><\/td>\n\u5b50\u8fdb\u7a0b\u9000\u51fa\u540e\u7236\u8fdb\u7a0b\u6ca1\u56de\u6536（\u50f5\u5c38\u8fdb\u7a0b）<\/td>\n\u52a0\u4e0a\u00a0signal(SIGCHLD, sigchld_handler)\u00a0\u548c\u00a0waitpid\u00a0\u5faa\u73af<\/td>\n<\/tr>\n
        thread_server\u00a0\u7f16\u8bd1\u62a5\u00a0undefined reference to pthread_create<\/td>\n\u6ca1\u94fe\u63a5 pthread \u5e93<\/td>\n\u7f16\u8bd1\u547d\u4ee4\u52a0\u4e0a\u00a0-lpthread：gcc thread_server.c -o thread_server -lpthread<\/td>\n<\/tr>\n
        \u591a\u7ebf\u7a0b\u670d\u52a1\u5668\u884c\u4e3a\u602a\u5f02，\u4e24\u4e2a\u5ba2\u6237\u7aef\u6536\u5230\u7684\u5185\u5bb9\u4e92\u76f8\u4e32<\/td>\n\u53c2\u6570\u4f20\u9012\u7528\u4e86\u6808\u53d8\u91cf\u5730\u5740<\/td>\n\u5fc5\u987b\u00a0malloc\u00a0\u5728\u5806\u4e0a\u5206\u914d，\u7ebf\u7a0b\u5185\u00a0free<\/td>\n<\/tr>\n
        select\u00a0\u670d\u52a1\u5668\u6700\u591a\u53ea\u80fd\u8fde 1024 \u4e2a\u5ba2\u6237\u7aef<\/td>\nFD_SETSIZE \u786c\u9650\u5236<\/td>\n\u6362\u6210 poll \u6216 epoll<\/td>\n<\/tr>\n
        epoll_wait\u00a0\u8fd4\u56de\u4e86\u4e8b\u4ef6，\u4f46\u00a0read\u00a0\u65f6\u6ca1\u6709\u6570\u636e<\/td>\n\u53ef\u80fd\u662f ET \u6a21\u5f0f\u4e0b\u6ca1\u5faa\u73af\u8bfb\u5230\u5e95<\/td>\nET \u6a21\u5f0f\u5fc5\u987b\u5faa\u73af\u00a0read\u00a0\u76f4\u5230\u00a0errno == EAGAIN<\/td>\n<\/tr>\n
        epoll_ctl\u00a0\u62a5\u00a0Bad file descriptor<\/td>\nfd \u5df2\u7ecf\u88ab close \u4f46\u6ca1\u4ece epoll \u5220\u9664<\/td>\n\u5173\u95ed fd \u524d\u5148\u00a0epoll_ctl(…, EPOLL_CTL_DEL, fd, NULL)<\/td>\n<\/tr>\n
        bind: Address already in use<\/td>\n\u4e0a\u6b21\u670d\u52a1\u5668\u9000\u51fa\u540e\u7aef\u53e3\u8fd8\u5904\u4e8e TIME_WAIT \u72b6\u6001<\/td>\n\u52a0\u4e0a\u00a0setsockopt(…, SO_REUSEADDR, …)<\/td>\n<\/tr>\n
        ET \u6a21\u5f0f\u670d\u52a1\u5668\u8dd1\u7740\u8dd1\u7740\u4e0d\u52a8\u4e86<\/td>\nfd \u6ca1\u8bbe\u975e\u963b\u585e，read \u963b\u585e\u5728\u67d0\u4e2a\u5ba2\u6237\u7aef\u4e0a<\/td>\n\u6240\u6709 ET \u6a21\u5f0f\u4e0b\u7684 fd \u5fc5\u987b\u5148\u00a0fcntl(fd, F_SETFL, O_NONBLOCK)<\/td>\n<\/tr>\n
        \u5ba2\u6237\u7aef\u65ad\u5f00\u540e\u670d\u52a1\u5668 CPU \u98d9\u5347<\/td>\n\u6ca1\u6709\u6b63\u786e\u5904\u7406 read \u8fd4\u56de 0 \u7684\u60c5\u51b5，\u7a7a\u8f6c\u5faa\u73af<\/td>\n\u68c0\u67e5\u00a0read\u00a0\u8fd4\u56de\u503c：<=0\u00a0\u65f6\u5173\u95ed fd \u5e76\u4ece\u76d1\u63a7\u5217\u8868\u79fb\u9664<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
        \n

        \u77e5\u8bc6\u70b9\u5173\u7cfb\u56fe<\/h3>\n

        \u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510
        \n \u2502 \u7f51\u7edc\u7f16\u7a0b\u57fa\u7840（Day 22-23） \u2502
        \n \u2502 socket \/ bind \/ listen \/ accept \u2502
        \n \u2502 TCP Echo \u670d\u52a1\u5668 \u2502
        \n \u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u252c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518
        \n \u2502
        \n \u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2534\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510
        \n \u2502 \u5e76\u53d1\u670d\u52a1\u5668（Day 24-25） \u2502
        \n \u2514\u2500\u2500\u2500\u2500\u2500\u2500\u252c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u252c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518
        \n \u2502 \u2502
        \n \u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2534\u2500\u2500\u2510 \u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2534\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510
        \n \u2502 \u591a\u8fdb\u7a0b Fork \u2502 \u2502 \u591a\u7ebf\u7a0b Pthread \u2502
        \n \u2502 \u6bcf\u5ba2\u6237=1\u8fdb\u7a0b \u2502 \u2502 \u6bcf\u5ba2\u6237=1\u7ebf\u7a0b \u2502
        \n \u2514\u2500\u2500\u2500\u2500\u2500\u2500\u252c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518 \u2514\u2500\u2500\u2500\u2500\u2500\u2500\u252c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518
        \n \u2502 \u2502
        \n \u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u252c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518
        \n \u2502 \u90fd\u65e0\u6cd5\u9ad8\u6548\u652f\u6491\u6d77\u91cf\u8fde\u63a5
        \n \u2502
        \n \u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2534\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510
        \n \u2502 IO \u590d\u7528\u6280\u672f \u2502
        \n \u2502 \u2502
        \n \u2502 select \u2500\u2500\u2192 poll \u2500\u2500\u2192 epoll（\u738b\u8005） \u2502
        \n \u2502 1983 1997 2002 \u2502
        \n \u2502 O(n) O(n) O(1) \u2502
        \n \u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u252c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518
        \n \u2502
        \n \u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2534\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510
        \n \u2502 Reactor \/ Proactor \u6a21\u5f0f \u2502
        \n \u2502 （\u8fdb\u9636：\u6846\u67b6\u8bbe\u8ba1\u6a21\u5f0f） \u2502
        \n \u2502 \u2502
        \n \u2502 Nginx\u3001Redis\u3001Netty\u3001libuv \u7684\u57fa\u77f3 \u2502
        \n \u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518<\/p>\n

        \n

        📌 \u4f5c\u4e1a（Day 24-25 \u5de9\u56fa）<\/h3>\n
      • \u57fa\u7840：\u5206\u522b\u7f16\u8bd1\u8fd0\u884c\u591a\u8fdb\u7a0b\u548c\u591a\u7ebf\u7a0b\u670d\u52a1\u5668，\u7528\u00a0telnet\u00a0\u5f00 3 \u4e2a\u5ba2\u6237\u7aef\u540c\u65f6\u8fde\u63a5，\u7528\u00a0ps\u00a0\u89c2\u5bdf\u8fdb\u7a0b\/\u7ebf\u7a0b\u6570\u91cf\u7684\u53d8\u5316\u3002<\/li>\n
      • \u5b9e\u9a8c：\u5728\u591a\u7ebf\u7a0b\u670d\u52a1\u5668\u4e2d，\u6545\u610f\u4e0d\u5173\u95ed\u00a0server_fd\u00a0\u6216\u6545\u610f\u4e0d\u8bbe\u7f6e\u7ebf\u7a0b\u5206\u79bb，\u7528\u00a0htop\u00a0\u6216\u00a0ps\u00a0\u89c2\u5bdf\u8d44\u6e90\u6cc4\u6f0f\u73b0\u8c61\u3002<\/li>\n
      • \u52a8\u624b：\u628a\u4efb\u610f\u4e00\u4e2a\u670d\u52a1\u5668\u7684\u5ba2\u6237\u7aef\u5957\u63a5\u5b57\u7528\u00a0fcntl\u00a0\u8bbe\u4e3a\u975e\u963b\u585e，\u7136\u540e\u5728\u00a0read\u00a0\u65f6\u52a0\u5165\u5bf9\u00a0EAGAIN\u00a0\u7684\u5224\u65ad，\u4f53\u4f1a\u975e\u963b\u585e\u8bfb\u7684\u884c\u4e3a\u3002<\/li>\n
      • \u5bf9\u6bd4：\u5206\u522b\u7f16\u8bd1\u8fd0\u884c select\u3001poll\u3001epoll \u4e09\u4e2a\u670d\u52a1\u5668，\u7528\u7b2c\u516d\u90e8\u5206\u7684 Python \u811a\u672c\u521b\u5efa 500 \u4e2a\u8fde\u63a5，\u7528\u00a0top\u00a0\u5bf9\u6bd4\u4e09\u8005\u7684 CPU \u5360\u7528\u3002<\/li>\n
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        \n

        \u5e76\u53d1\u4e4b\u8def\u6f2b\u6f2b，\u4ece\u00a0fork\u00a0\u5230\u00a0pthread\u00a0\u518d\u5230\u00a0epoll，\u4f60\u5df2\u7ecf\u638c\u63e1\u4e86 Linux \u7f51\u7edc\u7f16\u7a0b\u7684"\u4e09\u628a\u94a5\u5319"\u3002\u4eca\u5929\u5199\u7684\u00a0epoll_server.c，\u5c31\u662f Nginx \u548c Redis \u8bde\u751f\u7684\u7b2c\u4e00\u884c\u4ee3\u7801\u3002\u6211\u4eec\u4e0b\u671f\u9879\u76ee\u89c1！<\/p>\n","protected":false},"excerpt":{"rendered":"

        \u5355\u8fde\u63a5\u7684 Echo \u670d\u52a1\u5668\u5c31\u50cf\u4e00\u5bb6\u53ea\u6709\u4e00\u4e2a\u670d\u52a1\u5458\u7684\u9910\u9986\u2014\u2014\u5ba2\u4eba\u6765\u4e86\u5f97\u6392\u961f\u7b49\u3002\u4eca\u5929\u6211\u4eec\u7ed9\u9910\u5385\u62db\u6ee1\\”\u670d\u52a1\u5458\\”（\u8fdb\u7a0b\/\u7ebf\u7a0b），\u518d\u7ed9\u6bcf\u4e2a\u4eba\u914d\u4e0a\u4e00\u90e8\\”\u667a\u80fd\u5bf9\u8bb2\u673a\\”（epoll），\u8ba9\u5ba2\u4eba\u4eec\u968f\u5230\u968f\u5403，\u540c\u65f6\u8fd8\u80fd\u76d1\u63a7\u540e\u53a8\u3001\u6536\u94f6\u53f0\u3001\u5916\u5356\u7a97\u53e3，\u771f\u6b63\u5b9e\u73b0\u591a\u9762\u624b\u3002\u524d\u8a00\u5728 Day 22-23 \u4e2d，\u6211\u4eec\u5b9e\u73b0\u4e86\u4e00\u4e2a\u6807\u51c6\u7684 TCP Echo \u670d\u52a1\u5668\u3002\u4f46\u5b83\u6709\u4e00\u4e2a\u81f4\u547d\u7684\u7f3a\u9677：<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[10187,174,58,43],"topic":[],"class_list":["post-91168","post","type-post","status-publish","format-standard","hentry","category-server","tag-codingplan","tag-c","tag-linux","tag-43"],"yoast_head":"\nDay 24-25 \u5e76\u53d1\u670d\u52a1\u5668 + IO\u590d\u7528\uff1a\u8ba9\u4f60\u7684\u7a0b\u5e8f\u540c\u65f6\u670d\u52a1\u6210\u5343\u4e0a\u4e07\u4e2a\u201c\u5ba2\u4eba\u201c - 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