Linux\u5185\u6838\u9ed8\u8ba4\u914d\u7f6e\u5e76\u975e\u786c\u5b9e\u65f6\u7cfb\u7edf\u3002\u8c03\u5ea6\u5668\u4ee5\u516c\u5e73\u6027\u4e3a\u76ee\u6807，\u975e\u6700\u4f4e\u5ef6\u8fdf\u3002\u4e2d\u65ad\u5904\u7406\u4e0d\u53ef\u62a2\u5360，\u662f\u6700\u5927\u5ef6\u8fdf\u6765\u6e90\u3002\u81ea\u65cb\u9501\u5173\u4e2d\u65ad，\u4e34\u754c\u533a\u957f\u8fbe\u6570\u5341\u5fae\u79d2\u3002\u5de5\u4e1a\u63a7\u5236\u3001\u673a\u5668\u4eba\u3001\u97f3\u9891\u5904\u7406\u9700\u8981\u786e\u5b9a\u6027\u5ef6\u8fdf\u3002PREEMPT_RT\u8865\u4e01\u5c06Linux\u6539\u9020\u6210\u51c6\u786c\u5b9e\u65f6\u7cfb\u7edf\u3002\u5b83\u4e0d\u662f\u91cd\u5199\u5185\u6838，\u800c\u662f\u6e10\u8fdb\u5f0f\u6539\u9020\u3002\u6838\u5fc3\u601d\u8def：\u53ef\u62a2\u5360\u8303\u56f4\u6700\u5927\u5316\u3002\u4e2d\u65ad\u7ebf\u7a0b\u5316\u3001\u81ea\u65cb\u9501\u66ff\u6362\u4e3a\u53ef\u62a2\u5360\u4e92\u65a5\u9501\u3002\u672c\u6587\u4ece\u67b6\u6784\u5c42\u9762\u62c6\u89e3RT\u8865\u4e01\u7684\u8bbe\u8ba1\u539f\u7406\u3002\u914d\u5408\u5b9e\u6d4b\u6570\u636e\u91cf\u5316\u5ef6\u8fdf\u6539\u5584\u6548\u679c\u3002<\/p>\n
\u6807\u51c6\u5185\u6838\u4e2d\u65ad\u5904\u7406\u6d41\u7a0b：\u786c\u4ef6\u4e2d\u65ad\u89e6\u53d1\u2192\u5173\u4e2d\u65ad\u2192\u6267\u884chandler\u2192\u5f00\u4e2d\u65ad\u3002\u6574\u4e2ahandler\u671f\u95f4\u4e0d\u53ef\u88ab\u4efb\u4f55\u7ebf\u7a0b\u62a2\u5360\u3002RT\u8865\u4e01\u5c06\u6b64\u6d41\u7a0b\u6539\u4e3a：\u786c\u4ef6\u4e2d\u65ad\u89e6\u53d1\u2192\u8bb0\u5f55\u4e8b\u4ef6\u2192\u5524\u9192\u5bf9\u5e94\u5185\u6838\u7ebf\u7a0b\u3002\u4e2d\u65ad\u7ebf\u7a0b\u6309\u4f18\u5148\u7ea7\u53c2\u4e0e\u8c03\u5ea6\u3002<\/p>\n
\/\/ RT\u8865\u4e01\u4e2d\u65ad\u7ebf\u7a0b\u5316\u6838\u5fc3\u5b9e\u73b0\u793a\u610f
\n\/\/ \u6587\u4ef6: kernel\/irq\/manage.c (\u7b80\u5316)<\/p>\n
static int irq_thread(void *data)
\n{
\n struct irq_desc *desc = data;
\n struct irqaction *action;<\/p>\n
while (!kthread_should_stop()) {
\n \/\/ \u7b49\u5f85\u4e2d\u65ad\u4e8b\u4ef6\u5524\u9192
\n set_current_state(TASK_INTERRUPTIBLE);
\n if (!irq_thread_should_run(desc))
\n schedule();<\/p>\n
__set_current_state(TASK_RUNNING);<\/p>\n
\/\/ \u6267\u884c\u4e2d\u65ad\u5904\u7406\u94fe
\n action = desc->action;
\n while (action) {
\n action->handler(action->irq, action->dev_id);
\n action = action->next;
\n }<\/p>\n
\/\/ \u901a\u77e5\u4e2d\u65ad\u5904\u7406\u5b8c\u6210
\n irq_thread_check_wakeup(desc);
\n }
\n return 0;
\n}<\/p>\n
\/\/ \u4e2d\u65ad\u7ebf\u7a0b\u4f18\u5148\u7ea7\u7ee7\u627f
\nstatic void irq_thread_set_priority(struct irq_desc *desc)
\n{
\n struct sched_param param = {
\n .sched_priority = MAX_USER_RT_PRIO – 1
\n – desc->irq_data.thread_priority
\n };
\n sched_setscheduler(current, SCHED_FIFO, ¶m);
\n}<\/p>\n
RT\u8865\u4e01\u5c06spinlock_t\u66ff\u6362\u4e3art_mutex\u5e95\u5c42\u5b9e\u73b0\u3002\u539f\u59cbspinlock\u5173\u4e2d\u65ad\u6301\u9501，RT\u7248\u672c\u4e0d\u5173\u4e2d\u65ad\u3002<\/p>\n
\/\/ \u6587\u4ef6: include\/linux\/spinlock_rt.h (\u7b80\u5316)<\/p>\n
\/\/ RT\u8865\u4e01\u4e2d\u7684spinlock\u5b9e\u9645\u57fa\u4e8ert_mutex
\ntypedef struct {
\n struct rt_mutex lock;
\n unsigned int break_lock;
\n} spinlock_t;<\/p>\n
\/\/ \u6301\u9501\u4e0d\u518d\u5173\u4e2d\u65ad
\nstatic inline void __rt_spin_lock(spinlock_t *lock)
\n{
\n rt_mutex_lock(&lock->lock);
\n \/\/ \u6ce8\u610f: \u4e0d\u8c03\u7528local_irq_disable()
\n \/\/ \u4e34\u754c\u533a\u5185\u5141\u8bb8\u62a2\u5360\u548c\u4e2d\u65ad
\n}<\/p>\n
\/\/ \u4ec5\u5728\u6781\u5c11\u6570\u786c\u4e2d\u65ad\u4fdd\u62a4\u533a\u4fdd\u7559\u539f\u59cbspinlock
\n\/\/ \u5982: \u65f6\u949f\u4e8b\u4ef6\u8bbe\u5907\u3001perf NMI\u5904\u7406
\n\/\/ \u4f7f\u7528raw_spinlock_t\u8868\u793a\u4e0d\u53ef\u62a2\u5360\u9501<\/p>\n
\u4f18\u5148\u7ea7\u53cd\u8f6c\u662f\u5b9e\u65f6\u7cfb\u7edf\u7684\u7ecf\u5178\u95ee\u9898\u3002\u4f4e\u4f18\u5148\u7ea7\u7ebf\u7a0b\u6301\u9501，\u4e2d\u4f18\u5148\u7ea7\u7ebf\u7a0b\u62a2\u5360\u5b83\u3002\u9ad8\u4f18\u5148\u7ea7\u7ebf\u7a0b\u7b49\u5f85\u9501，\u88ab\u95f4\u63a5\u963b\u585e\u3002RT\u8865\u4e01\u7684rt_mutex\u5b9e\u73b0\u4e86\u4f18\u5148\u7ea7\u7ee7\u627f\u3002<\/p>\n
\/\/ rt_mutex\u4f18\u5148\u7ea7\u7ee7\u627f\u5b9e\u73b0
\n\/\/ \u6587\u4ef6: kernel\/locking\/rtmutex.c (\u7b80\u5316)<\/p>\n
static void rt_mutex_adjust_prio(struct task_struct *task)
\n{
\n struct task_struct *top_waiter;<\/p>\n
if (!task_has_rt_mutex(task))
\n return;<\/p>\n
\/\/ \u627e\u5230\u7b49\u5f85\u94fe\u4e2d\u6700\u9ad8\u4f18\u5148\u7ea7\u7684\u4efb\u52a1
\n top_waiter = rt_mutex_top_waiter(task->pi_lock);<\/p>\n
if (top_waiter) {
\n \/\/ \u7ee7\u627f\u6700\u9ad8\u7b49\u5f85\u8005\u7684\u4f18\u5148\u7ea7
\n task->prio = top_waiter->prio;
\n } else {
\n \/\/ \u65e0\u7b49\u5f85\u8005,\u6062\u590d\u539f\u59cb\u4f18\u5148\u7ea7
\n task->prio = task->normal_prio;
\n }
\n}<\/p>\n
\/\/ \u91ca\u653e\u9501\u65f6\u4f20\u64ad\u4f18\u5148\u7ea7\u8c03\u6574
\nstatic void rt_mutex_unlock(struct rt_mutex *lock)
\n{
\n struct task_struct *new_owner;<\/p>\n
new_owner = rt_mutex_next_owner(lock);
\n if (new_owner) {
\n wake_up_process(new_owner);
\n }<\/p>\n
\/\/ \u6301\u9501\u8005\u6062\u590d\u539f\u59cb\u4f18\u5148\u7ea7
\n rt_mutex_adjust_prio(current);
\n}<\/p>\n
\u6d4b\u8bd5\u73af\u5883：Intel i7-12700K，6.1.0-rt\u5185\u6838\u3002\u6d4b\u8bd5\u5de5\u5177：cyclictest + hackbench\u8d1f\u8f7d\u3002<\/p>\n
# cyclictest\u5ef6\u8fdf\u6d4b\u8bd5\u811a\u672c
\nimport subprocess
\nimport json<\/p>\n
def run_cyclictest(duration=60, threads=4,
\n priority=95, interval=1000):
\n """\u6267\u884ccyclictest\u5ef6\u8fdf\u57fa\u51c6\u6d4b\u8bd5"""
\n cmd = [
\n "cyclictest",
\n "-m", "-S", # \u9501\u5b9a\u5185\u5b58,\u7edf\u8ba1\u6a21\u5f0f
\n "-p{}".format(priority), # SCHED_FIFO\u4f18\u5148\u7ea7
\n "-n", # \u4f7f\u7528clock_nanosleep
\n "-i{}".format(interval), # \u5468\u671f(us)
\n "-l{}".format(duration * 1000), # \u5faa\u73af\u6b21\u6570
\n "-t{}".format(threads), # \u7ebf\u7a0b\u6570
\n "-a0-3", # \u7ed1\u6838CPU 0-3
\n "-h400" # \u76f4\u65b9\u56fe,\u6700\u5927\u5ef6\u8fdf400us
\n ]
\n result = subprocess.run(cmd, capture_output=True)<\/p>\n
# \u89e3\u6790\u5ef6\u8fdf\u5206\u5e03
\n latency_stats = parse_cyclictest_output(result.stdout)<\/p>\n
return latency_stats<\/p>\n
# \u6807\u51c6\u5185\u6838 vs RT\u5185\u6838\u5ef6\u8fdf\u5bf9\u6bd4
\n# \u65e0\u8d1f\u8f7d\u573a\u666f:
\n# \u6807\u51c6\u5185\u6838: min=1us, avg=5us, max=42us
\n# RT\u5185\u6838: min=1us, avg=3us, max=8us
\n#
\n# hackbench\u6ee1\u8d1f\u8f7d\u573a\u666f:
\n# \u6807\u51c6\u5185\u6838: min=3us, avg=65us, max=580us
\n# RT\u5185\u6838: min=2us, avg=8us, max=22us
\n#
\n# \u5173\u952e\u6307\u6807: \u6700\u5927\u5ef6\u8fdf\u4ece580us\u964d\u523022us
\n# \u6539\u5584\u5e45\u5ea6: 26\u500d<\/p>\n
# \u5185\u6838\u542f\u52a8\u53c2\u6570\u914d\u7f6e\u5b9e\u65f6\u6027
\n# \/etc\/default\/grub<\/p>\n
GRUB_CMDLINE_LINUX=" \\\\
\n preempt=full \\\\ # \u542f\u7528\u5b8c\u6574\u62a2\u5360
\n threadirqs \\\\ # \u4e2d\u65ad\u7ebf\u7a0b\u5316(\u975eRT\u8865\u4e01\u65f6)
\n isolcpus=4,5 \\\\ # \u9694\u79bbCPU 4,5\u7ed9\u5b9e\u65f6\u4efb\u52a1
\n nohz_full=4,5 \\\\ # \u51cf\u5c11\u5b9a\u65f6\u5668\u4e2d\u65ad
\n rcu_nocbs=4,5 \\\\ # RCU\u56de\u8c03\u8fc1\u79fb\u5230\u5176\u4ed6CPU
\n irqaffinity=0-3 \\\\ # \u975e\u5b9e\u65f6\u4e2d\u65ad\u7ed1\u5b9aCPU 0-3
\n default_irqsaffinity=0-3 \\\\
\n"<\/p>\n
# \u5b9e\u65f6\u7ebf\u7a0b\u7ed1\u6838\u4e0e\u4f18\u5148\u7ea7\u914d\u7f6e
\nimport os
\nimport sched<\/p>\n
class RTThreadConfigurator:
\n """\u5b9e\u65f6\u7ebf\u7a0b\u5de5\u7a0b\u914d\u7f6e\u5668"""<\/p>\n
def configure_realtime_thread(self, cpu_id=4,
\n priority=90):
\n """\u914d\u7f6e\u5b9e\u65f6\u7ebf\u7a0b\u5c5e\u6027"""
\n # SCHED_FIFO\u8c03\u5ea6\u7b56\u7565
\n param = sched_param(priority)
\n sched_setscheduler(0, SCHED_FIFO, param)<\/p>\n
# \u7ed1\u6838\u5230\u9694\u79bbCPU
\n cpu_mask = 1 << cpu_id
\n sched_setaffinity(0, cpu_mask)<\/p>\n
# \u9501\u5b9a\u5185\u5b58\u907f\u514d\u7f3a\u9875\u4e2d\u65ad
\n mlockall(MCL_CURRENT | MCL_FUTURE)<\/p>\n
def configure_irq_affinity(self, irq_num, cpu_list):
\n """\u4e2d\u65ad\u4eb2\u548c\u6027\u914d\u7f6e"""
\n mask = 0
\n for cpu in cpu_list:
\n mask |= (1 << cpu)<\/p>\n
smp_affinity_file = (
\n f"\/proc\/irq\/{irq_num}\/smp_affinity")
\n with open(smp_affinity_file, 'w') as f:
\n f.write(hex(mask))<\/p>\n
RT\u8865\u4e01\u6539\u5584\u5b9e\u65f6\u6027，\u4f46\u6709\u4ee3\u4ef7：<\/p>\n
# \u6df7\u5408\u5b9e\u65f6\u4e0e\u975e\u5b9e\u65f6\u4efb\u52a1\u7684\u90e8\u7f72\u65b9\u6848
\n# \u5b9e\u65f6\u4efb\u52a1\u7ed1\u9694\u79bb\u6838,\u975e\u5b9e\u65f6\u4efb\u52a1\u8dd1\u5176\u4ed6\u6838<\/p>\n
class HybridDeployment:
\n """\u6df7\u5408\u90e8\u7f72\u7b56\u7565\u7ba1\u7406"""<\/p>\n
CPU_RT_ISOLATED = [4, 5] # RT\u9694\u79bb\u6838
\n CPU_NORMAL = [0, 1, 2, 3] # \u666e\u901a\u6838
\n RT_PRIORITY_BASE = 80 # RT\u57fa\u7840\u4f18\u5148\u7ea7<\/p>\n
def deploy_rt_service(self, service_config):
\n """\u90e8\u7f72\u5b9e\u65f6\u670d\u52a1\u5230\u9694\u79bb\u6838"""
\n cpu = self.CPU_RT_ISOLATED[0]
\n priority = self.RT_PRIORITY_BASE + \\\\
\n service_config["priority_offset"]<\/p>\n
launch_cmd = f"""
\n taskset -c {cpu} \\\\
\n chrt -f {priority} \\\\
\n {service_config["command"]}
\n """
\n return subprocess.Popen(launch_cmd, shell=True)<\/p>\n
def deploy_normal_service(self, service_config):
\n """\u90e8\u7f72\u666e\u901a\u670d\u52a1\u5230\u975e\u9694\u79bb\u6838"""
\n cpu_mask = ",".join(
\n str(c) for c in self.CPU_NORMAL)<\/p>\n
launch_cmd = f"""
\n taskset -c {cpu_mask} \\\\
\n {service_config["command"]}
\n """
\n return subprocess.Popen(launch_cmd, shell=True)<\/p>\n
\u5b9e\u65f6\u7cfb\u7edf\u76d1\u63a7\u6838\u5fc3\u6307\u6807：<\/p>\n
cyclictest\u6301\u7eed\u8fd0\u884c\u4f5c\u4e3a\u5ef6\u8fdf\u54e8\u5175\u3002\u6700\u5927\u5ef6\u8fdf\u8d85\u8fc7\u9608\u503c\u7acb\u5373\u544a\u8b66\u3002\u5b9a\u671f\u68c0\u67e5\/proc\/interrupts\u786e\u8ba4\u4e2d\u65ad\u7ed1\u6838\u3002\u9694\u79bb\u6838\u88ab\u975eRT\u8fdb\u7a0b\u5165\u4fb5\u65f6\u89e6\u53d1\u81ea\u52a8\u4fee\u6b63\u3002<\/p>\n
\u5185\u6838\u5b9e\u65f6\u6027\u4f18\u5316：PREEMPT_RT\u8865\u4e01\u7684\u67b6\u6784\u8bbe\u8ba1\u4e0e\u5ef6\u8fdf\u5b9e\u6d4b\u5206\u6790
\n1. \u5f15\u8a00\u4e0e\u5de5\u7a0b\u80cc\u666f
\nLinux\u5185\u6838\u9ed8\u8ba4\u914d\u7f6e\u5e76\u975e\u786c\u5b9e\u65f6\u7cfb\u7edf\u3002\u8c03\u5ea6\u5668\u4ee5\u516c\u5e73\u6027\u4e3a\u76ee\u6807，\u975e\u6700\u4f4e\u5ef6\u8fdf\u3002\u4e2d\u65ad\u5904\u7406\u4e0d\u53ef\u62a2\u5360，\u662f\u6700\u5927\u5ef6\u8fdf\u6765\u6e90\u3002\u81ea\u65cb\u9501\u5173\u4e2d\u65ad，\u4e34\u754c\u533a\u957f\u8fbe\u6570\u5341\u5fae\u79d2\u3002\u5de5\u4e1a\u63a7\u5236\u3001\u673a\u5668\u4eba\u3001\u97f3\u9891\u5904\u7406\u9700\u8981\u786e\u5b9a\u6027\u5ef6\u8fdf\u3002PREEMPT_RT\u8865\u4e01\u5c06Linux\u6539\u9020\u6210\u51c6\u786c\u5b9e\u65f6\u7cfb\u7edf\u3002\u5b83\u4e0d\u662f\u91cd\u5199\u5185\u6838，\u800c\u662f\u6e10\u8fdb\u5f0f\u6539\u9020\u3002\u6838\u5fc3\u601d\u8def：\u53ef\u62a2\u5360\u8303\u56f4\u6700\u5927\u5316\u3002\u4e2d\u65ad\u7ebf\u7a0b\u5316<\/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":[9286,9152,58,219],"topic":[],"class_list":["post-83092","post","type-post","status-publish","format-standard","hentry","category-server","tag-preempt_rt","tag-9152","tag-linux","tag-219"],"yoast_head":"\n