Re: [LTP] [PATCH] pthread_cond_signal/1-1: use sched_yield to sync threads

[Kang K. <Kai...@wi...>]

On 2012年07月19日 11:07, Kang Kai wrote:
> This case fails on mips board routerstation randomly. The root cause is
> that when main thread call usleep(100) after signal the child threads,
> no child thread is scheduled to run.  So the case fails.
>
> I update it to set main thread with a lower priority and child threads
> with a higher one, then call sched_yield and usleep in main thread will
> make sure that one of the child threads will be scheduled.
Hi Cyril,

Would you like to help me to review this patch?

Thanks a lot.
Kai

>
> Signed-off-by: Kang Kai<kai...@wi...>
> ---
>   .../interfaces/pthread_cond_signal/1-1.c           |   44 +++++++++++++++++++-
>   1 files changed, 42 insertions(+), 2 deletions(-)
>
> diff --git a/testcases/open_posix_testsuite/conformance/interfaces/pthread_cond_signal/1-1.c b/testcases/open_posix_testsuite/conformance/interfaces/pthread_cond_signal/1-1.c
> index bf55b31..77374bf 100644
> --- a/testcases/open_posix_testsuite/conformance/interfaces/pthread_cond_signal/1-1.c
> +++ b/testcases/open_posix_testsuite/conformance/interfaces/pthread_cond_signal/1-1.c
> @@ -12,6 +12,7 @@
>
>   #define _XOPEN_SOURCE 600
>
> +#include<errno.h>
>   #include<pthread.h>
>   #include<stdio.h>
>   #include<stdlib.h>
> @@ -20,6 +21,7 @@
>   #include "posixtest.h"
>
>   #define THREAD_NUM  3
> +#define SCHED_POLICY SCHED_FIFO
>
>   struct testdata
>   {
> @@ -77,6 +79,10 @@ int main()
>   {
>   	int i, rc;
>   	struct sigaction act;
> +	int pid;
> +	int policy;
> +	struct sched_param param;
> +	pthread_attr_t attr;
>
>   	if (pthread_mutex_init(&td.mutex, NULL) != 0) {
>   		fprintf(stderr,"Fail to initialize mutex\n");
> @@ -87,8 +93,35 @@ int main()
>   		return PTS_UNRESOLVED;
>   	}
>
> +	pid = getpid();
> +	param.sched_priority = sched_get_priority_min(SCHED_POLICY);
> +	if (sched_setscheduler(pid, SCHED_POLICY,&param) != 0) {
> +		fprintf(stderr, "Fail to set main thread scheduler.\n");
> +		if (errno == EPERM)
> +			fprintf(stderr, "Failed with EPERM: are you root?\n");
> +		return PTS_UNRESOLVED;
> +	}
> +
> +	if (pthread_attr_init(&attr) != 0) {
> +		fprintf(stderr, "Fail to init child thread attribute.\n");
> +		return PTS_UNRESOLVED;
> +	}
> +	if (pthread_attr_setschedpolicy(&attr, SCHED_POLICY) != 0) {
> +		fprintf(stderr, "Fail to set child thread schedule policy attribute.\n");
> +		return PTS_UNRESOLVED;
> +	}
> +	param.sched_priority += 10;
> +	if (pthread_attr_setschedparam(&attr,&param) != 0) {
> +		fprintf(stderr, "Fail to set child thread schedule priority attribute.\n");
> +		return PTS_UNRESOLVED;
> +	}
> +	if (pthread_attr_setinheritsched(&attr, PTHREAD_EXPLICIT_SCHED) != 0) {
> +		fprintf(stderr, "Fail to set child thread inheritace attribute.\n");
> +		return PTS_UNRESOLVED;
> +	}
> +
>   	for (i=0; i<THREAD_NUM; i++) {	/* create THREAD_NUM threads */
> -	    	if (pthread_create(&thread[i], NULL, thr_func, NULL) != 0) {
> +		if (pthread_create(&thread[i],&attr, thr_func, NULL) != 0) {
>   			fprintf(stderr,"Fail to create thread[%d]\n", i);
>   			exit(PTS_UNRESOLVED);
>   		}
> @@ -96,6 +129,8 @@ int main()
>   	while (start_num<  THREAD_NUM)	/* waiting for all threads started */
>   		usleep(100);
>
> +	pthread_attr_destroy(&attr);
> +
>   	/* Acquire the mutex to make sure that all waiters are currently
>   	   blocked on pthread_cond_wait */
>   	if (pthread_mutex_lock(&td.mutex) != 0) {
> @@ -142,6 +177,7 @@ int main()
>   			fprintf(stderr,"Main failed to signal the condition\n");
>   			exit(PTS_UNRESOLVED);
>   		}
> +		sched_yield();
>   		usleep(100);
>   	}
>
> @@ -158,6 +194,10 @@ int main()
>   			exit(PTS_UNRESOLVED);
>   		}
>   	}
> +
> +	pthread_mutex_destroy(&td.mutex);
> +	pthread_cond_destroy(&td.cond);
> +
>   	printf("Test PASSED\n");
>   	return PTS_PASS;
> -}
> \ No newline at end of file
> +}