Messages in this thread | | | Date | Wed, 14 Oct 2020 13:45:00 +0200 | From | Jiri Olsa <> | Subject | Re: [PATCH v2] perf bench: Use condition variables in numa. |
| |
On Mon, Oct 12, 2020 at 09:16:11AM -0700, Ian Rogers wrote:
SNIP
> @@ -483,6 +484,18 @@ static void init_global_mutex(pthread_mutex_t *mutex) > pthread_mutex_init(mutex, &attr); > } > > +/* > + * Return a process-shared (global) condition variable: > + */ > +static void init_global_cond(pthread_cond_t *cond) > +{ > + pthread_condattr_t attr; > + > + pthread_condattr_init(&attr); > + pthread_condattr_setpshared(&attr, PTHREAD_PROCESS_SHARED); > + pthread_cond_init(cond, &attr); > +} > + > static int parse_cpu_list(const char *arg) > { > p0.cpu_list_str = strdup(arg); > @@ -1136,15 +1149,18 @@ static void *worker_thread(void *__tdata) > if (g->p.serialize_startup) { > pthread_mutex_lock(&g->startup_mutex); > g->nr_tasks_started++; > + /* The last thread wakes the main process. */ > + if (g->nr_tasks_started == g->p.nr_tasks) > + pthread_cond_signal(&g->startup_cond);
should you remove the condition? it's not necessary and making this racy, no?
just single pthread_cond_signal should be enough, because the wait code is checking the number of tasks
jirka
| |