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.
---
testcases/realtime/func/matrix_mult/matrix_mult.c | 79 ++++-----------------
1 files changed, 14 insertions(+), 65 deletions(-)
diff --git a/testcases/realtime/func/matrix_mult/matrix_mult.c
b/testcases/realtime/func/matrix_mult/matrix_mult.c
index 3576427..8ea90a9 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->arg;
int cpuid;
+ int i;
cpuid = set_affinity();
if (cpuid == -1) {
@@ -187,47 +188,12 @@ void *concurrent_thread(void *thread)
printf("Thread %d: Affinity set to cpu%d\n", thread_id, cpuid);
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)
{
@@ -239,7 +205,7 @@ 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)
)
{
@@ -247,8 +213,6 @@ void main_thread(void)
exit(1);
}
- pthread_barrier_init(&mult_start, NULL, numcpus);
-
mult_index = malloc(sizeof(int) * numcpus);
if (!mult_index) {
perror("malloc");
@@ -261,12 +225,6 @@ 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) {
@@ -309,36 +267,27 @@ 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, (void
*)(intptr_t)j, 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);
/* Go back to normal prio before doing any disk activity */
set_priority_other(0);
@@ -394,6 +343,7 @@ int main(int argc, char *argv[])
* stats array).
*/
iterations = (int) (iterations / numcpus) * numcpus;
+ iterations_percpu = iterations/numcpus;
printf("\n---------------------------------------\n");
printf("Matrix Multiplication (SMP Performance)\n");
@@ -412,7 +362,6 @@ int main(int argc, char *argv[])
main_thread();
- join_threads();
return 0;
}
--
1.5.5.GIT
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