Re: [PATCH 9/9] perf bench: futex: Support operations for shared futexes

[Arnaldo Carvalho de Melo <acme@kernel.org>]

Em Mon, Jun 16, 2014 at 11:14:27AM -0700, Davidlohr Bueso escreveu:
> Unlike futex-hash, requeuing and wakeup benchmarks do not support
> shared futexes, limiting the usefulness of the programs. Correct
> this, and allow using the local -S parameter. The default remains
> using private futexes.

Also isn't this benchmark related to something Darren did? Just checking
why he isn't in the CC list, Darren, does this all sound fine to you?

- Arnaldo
 
> Signed-off-by: Davidlohr Bueso <davidlohr@hp.com>
> ---
>  tools/perf/bench/futex-hash.c    |  7 +++++--
>  tools/perf/bench/futex-requeue.c | 22 ++++++++++++++--------
>  tools/perf/bench/futex-wake.c    | 15 ++++++++++-----
>  3 files changed, 29 insertions(+), 15 deletions(-)
> 
> diff --git a/tools/perf/bench/futex-hash.c b/tools/perf/bench/futex-hash.c
> index 14791eb..5175171 100644
> --- a/tools/perf/bench/futex-hash.c
> +++ b/tools/perf/bench/futex-hash.c
> @@ -26,6 +26,7 @@ static unsigned int nsecs    = 10;
>  /* amount of futexes per thread */
>  static unsigned int nfutexes = 1024;
>  static bool fshared = false, done = false;
> +static int futex_flag = 0;
>  
>  struct timeval start, end, runtime;
>  static pthread_mutex_t thread_lock;
> @@ -74,8 +75,7 @@ static void *workerfn(void *arg)
>  			 * such as internal waitqueue handling, thus enlarging
>  			 * the critical region protected by hb->lock.
>  			 */
> -			ret = futex_wait(&w->futex[i], 1234, NULL,
> -					 fshared ? 0 : FUTEX_PRIVATE_FLAG);
> +			ret = futex_wait(&w->futex[i], 1234, NULL, futex_flag);
>  			if (bench_format == BENCH_FORMAT_DEFAULT &&
>  			    (!ret || errno != EAGAIN || errno != EWOULDBLOCK))
>  				warn("Non-expected futex return call");
> @@ -147,6 +147,9 @@ int bench_futex_hash(int argc, const char **argv,
>  	if (!worker)
>  		goto errmem;
>  
> +	if (!fshared)
> +		futex_flag = FUTEX_PRIVATE_FLAG;
> +
>  	if (bench_format == BENCH_FORMAT_DEFAULT) {
>  		printf("Run summary [PID %d]: %d threads, each operating on %d [%s] futexes for %d secs.\n\n",
>  		       getpid(), nthreads, nfutexes, fshared ? "shared":"private", nsecs);
> diff --git a/tools/perf/bench/futex-requeue.c b/tools/perf/bench/futex-requeue.c
> index 7b211c1..197537b 100644
> --- a/tools/perf/bench/futex-requeue.c
> +++ b/tools/perf/bench/futex-requeue.c
> @@ -30,15 +30,17 @@ static u_int32_t futex1 = 0, futex2 = 0;
>  static unsigned int nrequeue = 1;
>  
>  static pthread_t *worker;
> -static bool done = 0;
> +static bool done = false, fshared = false;
>  static pthread_mutex_t thread_lock;
>  static pthread_cond_t thread_parent, thread_worker;
>  static struct stats requeuetime_stats, requeued_stats;
>  static unsigned int ncpus, threads_starting, nthreads = 0;
> +static int futex_flag = 0;
>  
>  static const struct option options[] = {
>  	OPT_UINTEGER('t', "threads",  &nthreads, "Specify amount of threads"),
>  	OPT_UINTEGER('q', "nrequeue", &nrequeue, "Specify amount of threads to requeue at once"),
> +	OPT_BOOLEAN('S',  "shared",   &fshared,  "Use shared futexes instead of private ones"),
>  	OPT_END()
>  };
>  
> @@ -80,7 +82,7 @@ static void *workerfn(void *arg __maybe_unused)
>  	pthread_cond_wait(&thread_worker, &thread_lock);
>  	pthread_mutex_unlock(&thread_lock);
>  
> -	futex_wait(&futex1, 0, NULL, FUTEX_PRIVATE_FLAG);
> +	futex_wait(&futex1, 0, NULL, futex_flag);
>  	return NULL;
>  }
>  
> @@ -137,10 +139,13 @@ int bench_futex_requeue(int argc, const char **argv,
>  	if (!worker)
>  		err(EXIT_FAILURE, "calloc");
>  
> +	if (!fshared)
> +		futex_flag = FUTEX_PRIVATE_FLAG;
> +
>  	if (bench_format == BENCH_FORMAT_DEFAULT) {
> -		printf("Run summary [PID %d]: Requeuing %d threads (from %p to %p), "
> -		       "%d at a time.\n\n",
> -		       getpid(), nthreads, &futex1, &futex2, nrequeue);
> +		printf("Run summary [PID %d]: Requeuing %d threads (from [%s] futex %p to %p), "
> +		       "%d at a time.\n\n", getpid(), nthreads,
> +		       fshared ? "shared":"private", &futex1, &futex2, nrequeue);
>  	}
>  
>  	init_stats(&requeued_stats);
> @@ -173,8 +178,9 @@ int bench_futex_requeue(int argc, const char **argv,
>  			 * Do not wakeup any tasks blocked on futex1, allowing
>  			 * us to really measure futex_wait functionality.
>  			 */
> -			futex_cmp_requeue(&futex1, 0, &futex2, 0, nrequeue,
> -					  FUTEX_PRIVATE_FLAG);
> +			futex_cmp_requeue(&futex1, 0, &futex2, 0,
> +					  nrequeue, futex_flag);
> +
>  		gettimeofday(&end, NULL);
>  		timersub(&end, &start, &runtime);
>  
> @@ -187,7 +193,7 @@ int bench_futex_requeue(int argc, const char **argv,
>  		}
>  
>  		/* everybody should be blocked on futex2, wake'em up */
> -		nrequeued = futex_wake(&futex2, nthreads, FUTEX_PRIVATE_FLAG);
> +		nrequeued = futex_wake(&futex2, nthreads, futex_flag);
>  		if (nthreads != nrequeued)
>  			warnx("couldn't wakeup all tasks (%d/%d)", nrequeued, nthreads);
>  
> diff --git a/tools/perf/bench/futex-wake.c b/tools/perf/bench/futex-wake.c
> index eae6d09..08f62eb 100644
> --- a/tools/perf/bench/futex-wake.c
> +++ b/tools/perf/bench/futex-wake.c
> @@ -31,15 +31,17 @@ static u_int32_t futex1 = 0;
>  static unsigned int nwakes = 1;
>  
>  pthread_t *worker;
> -static bool done = false;
> +static bool done = false, fshared = false;
>  static pthread_mutex_t thread_lock;
>  static pthread_cond_t thread_parent, thread_worker;
>  static struct stats waketime_stats, wakeup_stats;
>  static unsigned int ncpus, threads_starting, nthreads = 0;
> +static int futex_flag = 0;
>  
>  static const struct option options[] = {
>  	OPT_UINTEGER('t', "threads", &nthreads, "Specify amount of threads"),
>  	OPT_UINTEGER('w', "nwakes",  &nwakes,   "Specify amount of threads to wake at once"),
> +	OPT_BOOLEAN('S',  "shared",  &fshared,  "Use shared futexes instead of private ones"),
>  	OPT_END()
>  };
>  
> @@ -57,7 +59,7 @@ static void *workerfn(void *arg __maybe_unused)
>  	pthread_cond_wait(&thread_worker, &thread_lock);
>  	pthread_mutex_unlock(&thread_lock);
>  
> -	futex_wait(&futex1, 0, NULL, FUTEX_PRIVATE_FLAG);
> +	futex_wait(&futex1, 0, NULL, futex_flag);
>  	return NULL;
>  }
>  
> @@ -140,10 +142,13 @@ int bench_futex_wake(int argc, const char **argv,
>  	if (!worker)
>  		err(EXIT_FAILURE, "calloc");
>  
> +	if (!fshared)
> +		futex_flag = FUTEX_PRIVATE_FLAG;
> +
>  	if (bench_format == BENCH_FORMAT_DEFAULT)
> -		printf("Run summary [PID %d]: blocking on %d threads (at futex %p), "
> +		printf("Run summary [PID %d]: blocking on %d threads (at [%s] futex %p), "
>  		       "waking up %d at a time.\n\n",
> -		       getpid(), nthreads, &futex1, nwakes);
> +		       getpid(), nthreads, fshared ? "shared":"private",  &futex1, nwakes);
>  
>  	init_stats(&wakeup_stats);
>  	init_stats(&waketime_stats);
> @@ -171,7 +176,7 @@ int bench_futex_wake(int argc, const char **argv,
>  		/* Ok, all threads are patiently blocked, start waking folks up */
>  		gettimeofday(&start, NULL);
>  		while (nwoken != nthreads)
> -			nwoken += futex_wake(&futex1, nwakes, FUTEX_PRIVATE_FLAG);
> +			nwoken += futex_wake(&futex1, nwakes, futex_flag);
>  		gettimeofday(&end, NULL);
>  		timersub(&end, &start, &runtime);
>  
> -- 
> 1.8.1.4