Commit 59c26660 authored by Ian Rogers's avatar Ian Rogers Committed by Arnaldo Carvalho de Melo
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perf sched: Fixes for thread safety analysis 



Add annotations to describe lock behavior. Add unlocks so that mutexes
aren't conditionally held on exit from perf_sched__replay. Add an exit
variable so that thread_func can terminate, rather than leaving the
threads blocked on mutexes.

Signed-off-by: default avatarIan Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexandre Truong <alexandre.truong@arm.com>
Cc: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andres Freund <andres@anarazel.de>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: André Almeida <andrealmeid@igalia.com>
Cc: Athira Jajeev <atrajeev@linux.vnet.ibm.com>
Cc: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Cc: Colin Ian King <colin.king@intel.com>
Cc: Dario Petrillo <dario.pk1@gmail.com>
Cc: Darren Hart <dvhart@infradead.org>
Cc: Dave Marchevsky <davemarchevsky@fb.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Fangrui Song <maskray@google.com>
Cc: Hewenliang <hewenliang4@huawei.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jason Wang <wangborong@cdjrlc.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Kim Phillips <kim.phillips@amd.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Martin Liška <mliska@suse.cz>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Pavithra Gurushankar <gpavithrasha@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Quentin Monnet <quentin@isovalent.com>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Remi Bernon <rbernon@codeweavers.com>
Cc: Riccardo Mancini <rickyman7@gmail.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Cc: Tom Rix <trix@redhat.com>
Cc: Weiguo Li <liwg06@foxmail.com>
Cc: Wenyu Liu <liuwenyu7@huawei.com>
Cc: William Cohen <wcohen@redhat.com>
Cc: Zechuan Chen <chenzechuan1@huawei.com>
Cc: bpf@vger.kernel.org
Cc: llvm@lists.linux.dev
Cc: yaowenbin <yaowenbin1@huawei.com>
Link: https://lore.kernel.org/r/20220826164242.43412-17-irogers@google.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent bfa339ce

tools/perf/builtin-sched.c

+29 −17
Original line number Diff line number Diff line
@@ -246,6 +246,7 @@ struct perf_sched { 
	const char	*time_str;

	struct perf_time_interval ptime;

	struct perf_time_interval hist_time;

	volatile bool   thread_funcs_exit;

};



/* per thread run time data */
@@ -633,7 +634,8 @@ static void *thread_func(void *ctx) 
	prctl(PR_SET_NAME, comm2);

	if (fd < 0)

		return NULL;

again:



	while (!sched->thread_funcs_exit) {

		ret = sem_post(&this_task->ready_for_work);

		BUG_ON(ret);

		mutex_lock(&sched->start_work_mutex);
@@ -653,11 +655,13 @@ static void *thread_func(void *ctx) 


		mutex_lock(&sched->work_done_wait_mutex);

		mutex_unlock(&sched->work_done_wait_mutex);



	goto again;

	}

	return NULL;

}



static void create_tasks(struct perf_sched *sched)

	EXCLUSIVE_LOCK_FUNCTION(sched->start_work_mutex)

	EXCLUSIVE_LOCK_FUNCTION(sched->work_done_wait_mutex)

{

	struct task_desc *task;

	pthread_attr_t attr;
@@ -687,6 +691,8 @@ static void create_tasks(struct perf_sched *sched) 
}



static void wait_for_tasks(struct perf_sched *sched)

	EXCLUSIVE_LOCKS_REQUIRED(sched->work_done_wait_mutex)

	EXCLUSIVE_LOCKS_REQUIRED(sched->start_work_mutex)

{

	u64 cpu_usage_0, cpu_usage_1;

	struct task_desc *task;
@@ -738,6 +744,8 @@ static void wait_for_tasks(struct perf_sched *sched) 
}



static void run_one_test(struct perf_sched *sched)

	EXCLUSIVE_LOCKS_REQUIRED(sched->work_done_wait_mutex)

	EXCLUSIVE_LOCKS_REQUIRED(sched->start_work_mutex)

{

	u64 T0, T1, delta, avg_delta, fluct;
@@ -3309,11 +3317,15 @@ static int perf_sched__replay(struct perf_sched *sched) 
	print_task_traces(sched);

	add_cross_task_wakeups(sched);



	sched->thread_funcs_exit = false;

	create_tasks(sched);

	printf("------------------------------------------------------------\n");

	for (i = 0; i < sched->replay_repeat; i++)

		run_one_test(sched);



	sched->thread_funcs_exit = true;

	mutex_unlock(&sched->start_work_mutex);

	mutex_unlock(&sched->work_done_wait_mutex);

	return 0;

}