Gilles Carry wrote:
> From: gilles.carry <gilles.carry>
>
> Syscall sched_setaffinity fails if choosen cpu is not online.
> In set_affinity, thread_id value is used as cpuid when calling
> sched_setaffinity. This fails when disabling cpus because threads ids
> and online cpu ids don't necessarly match.
>
> This patch simply increments cpuid (max. 8192) until it finds an online cpu.
> This guaranties that no more than one thread is assigned to one cpu.
> If set_affinity is called more times than there are online cpus
> then matrix_mult.c fails.
>
> Signed-off-by: Gilles Carry <[EMAIL PROTECTED]>
Acked-by: Darren Hart <[EMAIL PROTECTED]>
> ---
> testcases/realtime/func/matrix_mult/matrix_mult.c | 56 +++++++++++++-------
> 1 files changed, 36 insertions(+), 20 deletions(-)
>
> diff --git a/testcases/realtime/func/matrix_mult/matrix_mult.c
> b/testcases/realtime/func/matrix_mult/matrix_mult.c
> index 21fded8..afaca06 100644
> --- a/testcases/realtime/func/matrix_mult/matrix_mult.c
> +++ b/testcases/realtime/func/matrix_mult/matrix_mult.c
> @@ -44,6 +44,7 @@
> #include <libjvmsim.h>
> #include <libstats.h>
>
> +#define MAX_CPUS 8192
> #define PRIO 43
> #define MATRIX_SIZE 100
> #define DEF_OPS 8 /* the higher the number, the
> more CPU intensive */
> @@ -66,15 +67,13 @@ static float criteria;
> static int *mult_index;
> static int *tids;
> static int *flags;
> +static int online_cpu_id = -1;
>
> stats_container_t sdat, cdat, *curdat;
> stats_container_t shist, chist;
> static pthread_barrier_t mult_start;
> +static pthread_mutex_t mutex_cpu;
>
> -int gettid(void)
> -{
> - return syscall(__NR_gettid);
> -}
>
> void usage(void)
> {
> @@ -148,28 +147,39 @@ void matrix_mult_record(int m_size, int index)
> curdat->records[index].y = delta;
> }
>
> -int set_affinity(int cpuid)
> +int set_affinity(void)
> {
> - int tid = gettid();
> cpu_set_t mask;
> -
> - CPU_ZERO(&mask);
> - CPU_SET(cpuid, &mask);
> -
> - if (sched_setaffinity(0, sizeof(mask), &mask) < 0) {
> - printf("Thread %d: Can't set affinity: %s\n", tid,
> strerror(errno));
> - exit(1);
> - }
> -
> - return 0;
> + int cpuid;
> +
> + pthread_mutex_lock(&mutex_cpu);
> + do {
> + ++online_cpu_id;
> + CPU_ZERO(&mask);
> + CPU_SET(online_cpu_id, &mask);
> +
> + if (!sched_setaffinity(0, sizeof(mask), &mask)) {
> + cpuid = online_cpu_id; /* Save this value before
> unlocking mutex */
> + pthread_mutex_unlock(&mutex_cpu);
> + return cpuid;
> + }
> + } while (online_cpu_id < MAX_CPUS);
> + pthread_mutex_unlock(&mutex_cpu);
> + return -1;
> }
>
> void *concurrent_thread(void *thread)
> {
> struct thread *t = (struct thread *)thread;
> - int thread_id = (intptr_t)t->arg;
> + int thread_id = (intptr_t)t->id;
> + int cpuid;
> +
> + cpuid = set_affinity();
> + if (cpuid == -1) {
> + fprintf(stderr, "Thread %d: Can't set affinity.\n", thread_id);
> + exit(1);
> + }
>
> - set_affinity(thread_id);
> pthread_barrier_wait(&mult_start);
> while (flags[thread_id] != THREAD_DONE) {
> pthread_mutex_lock(&t->mutex);
> @@ -219,6 +229,7 @@ void main_thread(void)
> nsec_t start, end;
> long smin = 0, smax = 0, cmin = 0, cmax = 0, delta = 0;
> float savg, cavg;
> + int cpuid;
>
> if ( stats_container_init(&sdat, ITERATIONS) ||
> stats_container_init(&shist, HIST_BUCKETS) ||
> @@ -251,7 +262,12 @@ void main_thread(void)
> }
> memset(flags, 0, numcpus);
>
> - set_affinity(numcpus-1);
> + cpuid = set_affinity();
> + if (cpuid == -1) {
> + fprintf(stderr, "Main thread: Can't set affinity.\n");
> + exit(1);
> + }
> +
>
> /* run matrix mult operation sequentially */
> curdat = &sdat;
> @@ -284,7 +300,7 @@ void main_thread(void)
>
> /* Create numcpus-1 concurrent threads */
> for (j = 0; j < (numcpus-1); j++) {
> - tids[j] = create_fifo_thread(concurrent_thread, (void
> *)(intptr_t)j, PRIO);
> + tids[j] = create_fifo_thread(concurrent_thread, NULL, PRIO);
> if (tids[j] == -1) {
> printf("Thread creation failed (max threads
> exceeded?)\n");
> break;
--
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
[email protected]
https://lists.sourceforge.net/lists/listinfo/ltp-list
