[prev in list] [next in list] [prev in thread] [next in thread] 

List:       ltp-list
Subject:    Re: [LTP] [PATCH 3/4][RT][take#5] matrix_mult.c: thread
From:       Darren Hart <dvhltc () us ! ibm ! com>
Date:       2008-10-31 21:21:18
Message-ID: 490B76CE.8060607 () us ! ibm ! com
[Download RAW message or body]

Gilles Carry wrote:
> In concurrent calculations:
> - use a single pthread_barrier to start all threads together instead
> of a combination of barrier/mutex/condvar.
> - main thread no longer participates to concurrent calculations and simply
> performs rt_gettime(s) for global time spent evaluation.
> 
> Signed-off-by: Gilles Carry <gilles.carry@bull.net>

Acked-by: Darren Hart <dvhltc@us.ibm.com>

> ---
> testcases/realtime/func/matrix_mult/matrix_mult.c |   80 ++++-----------------
> 1 files changed, 15 insertions(+), 65 deletions(-)
> 
> diff --git a/testcases/realtime/func/matrix_mult/matrix_mult.c \
> b/testcases/realtime/func/matrix_mult/matrix_mult.c index 1b33154..368caaf 100644
> --- a/testcases/realtime/func/matrix_mult/matrix_mult.c
> +++ b/testcases/realtime/func/matrix_mult/matrix_mult.c
> @@ -66,9 +66,9 @@ static int numcpus;
> static float criteria;
> static int *mult_index;
> static int *tids;
> -static int *flags;
> static int online_cpu_id = -1;
> static int iterations = ITERATIONS;
> +static int iterations_percpu;
> 
> stats_container_t sdat, cdat, *curdat;
> stats_container_t shist, chist;
> @@ -178,6 +178,7 @@ void *concurrent_thread(void *thread)
> 	struct thread *t = (struct thread *)thread;
> 	int thread_id = (intptr_t)t->id;
> 	int cpuid;
> +	int i;
> 
> 	cpuid = set_affinity();
> 	if (cpuid == -1) {
> @@ -186,47 +187,12 @@ void *concurrent_thread(void *thread)
> 	}
> 
> 	pthread_barrier_wait(&mult_start);
> -	while (flags[thread_id] != THREAD_DONE) {
> -		pthread_mutex_lock(&t->mutex);
> -		flags[thread_id] = THREAD_WAIT;
> -		do {
> -			if (pthread_cond_wait(&t->cond, &t->mutex) != 0) {
> -				printf("cond_wait error!");
> -				exit(1);
> -			}
> -		} while (flags[thread_id] == THREAD_WAIT);
> -		pthread_mutex_unlock(&t->mutex);
> -		if (flags[thread_id] == THREAD_WORK)
> -			matrix_mult_record(MATRIX_SIZE, mult_index[thread_id]++);
> -	}
> +	for (i=0; i < iterations_percpu; i++)
> +		matrix_mult_record(MATRIX_SIZE, mult_index[thread_id]++);
> 
> 	return NULL;
> }
> 
> -void concurrent_ops(void)
> -{
> -	static int thread_id = 0;
> -
> -	if (thread_id < (numcpus-1)) {
> -		struct timespec nsleep;
> -		struct thread *t;
> -
> -		while (flags[thread_id] != THREAD_WAIT) {
> -			nsleep.tv_sec = 0;
> -			nsleep.tv_nsec = THREAD_SLEEP;
> -			nanosleep(&nsleep, NULL);
> -		}
> -		t = get_thread(tids[thread_id]);
> -		pthread_mutex_lock(&t->mutex);
> -		flags[thread_id] = THREAD_WORK;
> -		pthread_cond_signal(&t->cond);
> -		pthread_mutex_unlock(&t->mutex);
> -	} else
> -		matrix_mult_record(MATRIX_SIZE, mult_index[thread_id]++);
> -
> -	if (++thread_id == numcpus)
> -		thread_id = 0;
> -}
> 
> void main_thread(void)
> {
> @@ -238,7 +204,7 @@ void main_thread(void)
> 
> 	if (	stats_container_init(&sdat, iterations) ||
> 		stats_container_init(&shist, HIST_BUCKETS) ||
> -		stats_container_init(&cdat, iterations/numcpus) ||
> +		stats_container_init(&cdat, iterations_percpu) ||
> 		stats_container_init(&chist, HIST_BUCKETS)
> 	)
> 	{
> @@ -246,8 +212,6 @@ void main_thread(void)
> 		exit(1);
> 	}
> 
> -	pthread_barrier_init(&mult_start, NULL, numcpus);
> -
> 	mult_index = malloc(sizeof(int) * numcpus);
> 	if (!mult_index) {
> 		perror("malloc");
> @@ -260,12 +224,6 @@ void main_thread(void)
> 		exit(1);
> 	}
> 	memset(tids, 0, numcpus);
> -	flags = malloc(sizeof(int) * numcpus);
> -	if (!flags) {
> -		perror("malloc");
> -		exit(1);
> -	}
> -	memset(flags, 0, numcpus);
> 
> 	cpuid = set_affinity();
> 	if (cpuid == -1) {
> @@ -303,35 +261,27 @@ void main_thread(void)
> 		fprintf(stderr, "Warning: could not save sequential mults stats\n");
> 	}
> 
> +	pthread_barrier_init(&mult_start, NULL, numcpus+1);
> +	set_priority(PRIO);
> +	curdat = &cdat;
> +	online_cpu_id = -1; /* Redispatch cpus */
> 	/* Create numcpus-1 concurrent threads */
> -	for (j = 0; j < (numcpus-1); j++) {
> +	for (j = 0; j < numcpus; j++) {
> 		tids[j] = create_fifo_thread(concurrent_thread, NULL, PRIO);
> 		if (tids[j] == -1) {
> 			printf("Thread creation failed (max threads exceeded?)\n");
> -			break;
> +			exit(1);
> 		}
> 	}
> 
> -	pthread_barrier_wait(&mult_start);
> 
> 	/* run matrix mult operation concurrently */
> -	curdat = &cdat;
> -	printf("\nRunning concurrent operations (%dx)\n", iterations);
> +	pthread_barrier_wait(&mult_start);
> 	start = rt_gettime();
> -	for (i = 0; i < iterations; i++)
> -		concurrent_ops();
> +	join_threads();
> 	end = rt_gettime();
> -	delta = (long)((end - start)/NS_PER_US);
> -
> -	for (j = 0; j < (numcpus-1); j++) {
> -		struct thread *t;
> 
> -		t = get_thread(tids[j]);
> -		pthread_mutex_lock(&t->mutex);
> -		flags[j] = THREAD_DONE;
> -		pthread_cond_signal(&t->cond);
> -		pthread_mutex_unlock(&t->mutex);
> -	}
> +	delta = (long)((end - start)/NS_PER_US);
> 
> 	cavg = delta/iterations; /* don't use the stats record, use the total time \
> recorded */  cmin = stats_min(&cdat);
> @@ -396,6 +346,7 @@ int main(int argc, char *argv[])
> 		printf("Rounding up iterations value to nearest multiple of total online \
> CPUs\n"); 
> 	iterations = new_iterations;
> +	iterations_percpu = iterations / numcpus;
> 
> 	printf("Running %d iterations\n", iterations);
> 	printf("Matrix Dimensions: %dx%d\n", MATRIX_SIZE, MATRIX_SIZE);
> @@ -412,7 +363,6 @@ int main(int argc, char *argv[])
> 	set_priority(PRIO);
> 	main_thread();
> 
> -	join_threads();
> 
> 	return 0;
> }


-- 
Darren Hart
IBM Linux Technology Center
Real-Time Linux Team

-------------------------------------------------------------------------
This SF.Net email is sponsored by the Moblin Your Move Developer's challenge
Build the coolest Linux based applications with Moblin SDK & win great prizes
Grand prize is a trip for two to an Open Source event anywhere in the world
http://moblin-contest.org/redirect.php?banner_id=100&url=/
_______________________________________________
Ltp-list mailing list
Ltp-list@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/ltp-list


[prev in list] [next in list] [prev in thread] [next in thread]