Re: [PATCH 1/3] perf/bench-futex: Group test parameters cleanup

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

Em Thu, Aug 05, 2021 at 06:33:27PM -0700, Davidlohr Bueso escreveu:
> Do this across all futex-bench tests such that all program parameters
> are neatly in their own structure, which is nicer than how we have
> them now. No changes in program behavior are expected.
> 
> Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
> ---
>  tools/perf/bench/futex-hash.c          | 68 ++++++++++++++---------
>  tools/perf/bench/futex-lock-pi.c       | 66 +++++++++++++---------
>  tools/perf/bench/futex-requeue.c       | 76 ++++++++++++++++----------
>  tools/perf/bench/futex-wake-parallel.c | 69 +++++++++++++----------
>  tools/perf/bench/futex-wake.c          | 68 ++++++++++++++---------
>  5 files changed, 210 insertions(+), 137 deletions(-)
> 
> diff --git a/tools/perf/bench/futex-hash.c b/tools/perf/bench/futex-hash.c
> index b65373ce5c4f..2d86602f89e2 100644
> --- a/tools/perf/bench/futex-hash.c
> +++ b/tools/perf/bench/futex-hash.c
> @@ -29,11 +29,7 @@
>  
>  #include <err.h>
>  
> -static unsigned int nthreads = 0;
> -static unsigned int nsecs    = 10;
> -/* amount of futexes per thread */
> -static unsigned int nfutexes = 1024;
> -static bool fshared = false, done = false, silent = false;
> +static bool done = false;
>  static int futex_flag = 0;
>  
>  struct timeval bench__start, bench__end, bench__runtime;
> @@ -49,12 +45,30 @@ struct worker {
>  	unsigned long ops;
>  };
>  
> +struct parameters {
> +	unsigned int nthreads;
> +        unsigned int nfutexes;

tab please

> +	unsigned int runtime;
> +	bool silent;
> +	bool fshared;
> +};

Also aren't all these 'struct parameter' definitions almost the same?
Why not have it in a .h file shared by all these futex tests?

Also consider renaming it to something less generic so that things like
ctags stay happy, bench_futex_parms perhaps?

> +static struct parameters params = {
> +	.nfutexes = 1024,
> +	.runtime  = 10,
> +};
> +
>  static const struct option options[] = {
> -	OPT_UINTEGER('t', "threads", &nthreads, "Specify amount of threads"),
> -	OPT_UINTEGER('r', "runtime", &nsecs,    "Specify runtime (in seconds)"),
> -	OPT_UINTEGER('f', "futexes", &nfutexes, "Specify amount of futexes per threads"),
> -	OPT_BOOLEAN( 's', "silent",  &silent,   "Silent mode: do not display data/details"),
> -	OPT_BOOLEAN( 'S', "shared",  &fshared,  "Use shared futexes instead of private ones"),
> +	OPT_UINTEGER('t', "threads", &params.nthreads,
> +		     "Specify amount of threads"),

No need to break down these lines into multiple, keeping them as
one-liners should help reviewing a bit.

> +	OPT_UINTEGER('r', "runtime", &params.runtime,
> +		     "Specify runtime (in seconds)"),
> +	OPT_UINTEGER('f', "futexes", &params.nfutexes,
> +		     "Specify amount of futexes per threads"),
> +	OPT_BOOLEAN( 's', "silent",  &params.silent,
> +		     "Silent mode: do not display data/details"),
> +	OPT_BOOLEAN( 'S', "shared",  &params.fshared,
> +		     "Use shared futexes instead of private ones"),
>  	OPT_END()
>  };
>  
> @@ -78,7 +92,7 @@ static void *workerfn(void *arg)
>  	pthread_mutex_unlock(&thread_lock);
>  
>  	do {
> -		for (i = 0; i < nfutexes; i++, ops++) {
> +		for (i = 0; i < params.nfutexes; i++, ops++) {
>  			/*
>  			 * We want the futex calls to fail in order to stress
>  			 * the hashing of uaddr and not measure other steps,
> @@ -86,7 +100,7 @@ static void *workerfn(void *arg)
>  			 * the critical region protected by hb->lock.
>  			 */
>  			ret = futex_wait(&w->futex[i], 1234, NULL, futex_flag);
> -			if (!silent &&
> +			if (!params.silent &&
>  			    (!ret || errno != EAGAIN || errno != EWOULDBLOCK))
>  				warn("Non-expected futex return call");
>  		}
> @@ -112,7 +126,7 @@ static void print_summary(void)
>  	double stddev = stddev_stats(&throughput_stats);
>  
>  	printf("%sAveraged %ld operations/sec (+- %.2f%%), total secs = %d\n",
> -	       !silent ? "\n" : "", avg, rel_stddev_stats(stddev, avg),
> +	       !params.silent ? "\n" : "", avg, rel_stddev_stats(stddev, avg),
>  	       (int)bench__runtime.tv_sec);
>  }
>  
> @@ -141,30 +155,30 @@ int bench_futex_hash(int argc, const char **argv)
>  	act.sa_sigaction = toggle_done;
>  	sigaction(SIGINT, &act, NULL);
>  
> -	if (!nthreads) /* default to the number of CPUs */
> -		nthreads = cpu->nr;
> +	if (!params.nthreads) /* default to the number of CPUs */
> +		params.nthreads = cpu->nr;
>  
> -	worker = calloc(nthreads, sizeof(*worker));
> +	worker = calloc(params.nthreads, sizeof(*worker));
>  	if (!worker)
>  		goto errmem;
>  
> -	if (!fshared)
> +	if (!params.fshared)
>  		futex_flag = FUTEX_PRIVATE_FLAG;
>  
>  	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);
> +	       getpid(), params.nthreads, params.nfutexes, params.fshared ? "shared":"private", params.runtime);
>  
>  	init_stats(&throughput_stats);
>  	pthread_mutex_init(&thread_lock, NULL);
>  	pthread_cond_init(&thread_parent, NULL);
>  	pthread_cond_init(&thread_worker, NULL);
>  
> -	threads_starting = nthreads;
> +	threads_starting = params.nthreads;
>  	pthread_attr_init(&thread_attr);
>  	gettimeofday(&bench__start, NULL);
> -	for (i = 0; i < nthreads; i++) {
> +	for (i = 0; i < params.nthreads; i++) {
>  		worker[i].tid = i;
> -		worker[i].futex = calloc(nfutexes, sizeof(*worker[i].futex));
> +		worker[i].futex = calloc(params.nfutexes, sizeof(*worker[i].futex));
>  		if (!worker[i].futex)
>  			goto errmem;
>  
> @@ -189,10 +203,10 @@ int bench_futex_hash(int argc, const char **argv)
>  	pthread_cond_broadcast(&thread_worker);
>  	pthread_mutex_unlock(&thread_lock);
>  
> -	sleep(nsecs);
> +	sleep(params.runtime);
>  	toggle_done(0, NULL, NULL);
>  
> -	for (i = 0; i < nthreads; i++) {
> +	for (i = 0; i < params.nthreads; i++) {
>  		ret = pthread_join(worker[i].thread, NULL);
>  		if (ret)
>  			err(EXIT_FAILURE, "pthread_join");
> @@ -203,18 +217,18 @@ int bench_futex_hash(int argc, const char **argv)
>  	pthread_cond_destroy(&thread_worker);
>  	pthread_mutex_destroy(&thread_lock);
>  
> -	for (i = 0; i < nthreads; i++) {
> +	for (i = 0; i < params.nthreads; i++) {
>  		unsigned long t = bench__runtime.tv_sec > 0 ?
>  			worker[i].ops / bench__runtime.tv_sec : 0;
>  		update_stats(&throughput_stats, t);
> -		if (!silent) {
> -			if (nfutexes == 1)
> +		if (!params.silent) {
> +			if (params.nfutexes == 1)
>  				printf("[thread %2d] futex: %p [ %ld ops/sec ]\n",
>  				       worker[i].tid, &worker[i].futex[0], t);
>  			else
>  				printf("[thread %2d] futexes: %p ... %p [ %ld ops/sec ]\n",
>  				       worker[i].tid, &worker[i].futex[0],
> -				       &worker[i].futex[nfutexes-1], t);
> +				       &worker[i].futex[params.nfutexes-1], t);
>  		}
>  
>  		zfree(&worker[i].futex);
> diff --git a/tools/perf/bench/futex-lock-pi.c b/tools/perf/bench/futex-lock-pi.c
> index 89c6d160379c..9fc994beb933 100644
> --- a/tools/perf/bench/futex-lock-pi.c
> +++ b/tools/perf/bench/futex-lock-pi.c
> @@ -31,22 +31,36 @@ struct worker {
>  
>  static u_int32_t global_futex = 0;
>  static struct worker *worker;
> -static unsigned int nsecs = 10;
> -static bool silent = false, multi = false;
> -static bool done = false, fshared = false;
> -static unsigned int nthreads = 0;
> +static bool done = false;
>  static int futex_flag = 0;
>  static pthread_mutex_t thread_lock;
>  static unsigned int threads_starting;
>  static struct stats throughput_stats;
>  static pthread_cond_t thread_parent, thread_worker;
>  
> +struct parameters {
> +	unsigned int nthreads;
> +	unsigned int runtime;
> +	bool multi;
> +	bool silent;
> +	bool fshared;
> +};
> +
> +static struct parameters params = {
> +	.runtime  = 10,
> +};
> +
>  static const struct option options[] = {
> -	OPT_UINTEGER('t', "threads",  &nthreads, "Specify amount of threads"),
> -	OPT_UINTEGER('r', "runtime", &nsecs,     "Specify runtime (in seconds)"),
> -	OPT_BOOLEAN( 'M', "multi",   &multi,     "Use multiple futexes"),
> -	OPT_BOOLEAN( 's', "silent",  &silent,    "Silent mode: do not display data/details"),
> -	OPT_BOOLEAN( 'S', "shared",  &fshared,   "Use shared futexes instead of private ones"),
> +	OPT_UINTEGER('t', "threads", &params.nthreads,
> +		     "Specify amount of threads"),
> +	OPT_UINTEGER('r', "runtime", &params.runtime,
> +		     "Specify runtime (in seconds)"),
> +	OPT_BOOLEAN( 'M', "params.multi", &params.multi,
> +		     "Use params.multiple futexes"),
> +	OPT_BOOLEAN( 's', "params.silent",  &params.silent,
> +		     "Params.Silent mode: do not display data/details"),
> +	OPT_BOOLEAN( 'S', "shared",  &params.fshared,
> +		     "Use shared futexes instead of private ones"),
>  	OPT_END()
>  };
>  
> @@ -61,7 +75,7 @@ static void print_summary(void)
>  	double stddev = stddev_stats(&throughput_stats);
>  
>  	printf("%sAveraged %ld operations/sec (+- %.2f%%), total secs = %d\n",
> -	       !silent ? "\n" : "", avg, rel_stddev_stats(stddev, avg),
> +	       !params.silent ? "\n" : "", avg, rel_stddev_stats(stddev, avg),
>  	       (int)bench__runtime.tv_sec);
>  }
>  
> @@ -93,7 +107,7 @@ static void *workerfn(void *arg)
>  		ret = futex_lock_pi(w->futex, NULL, futex_flag);
>  
>  		if (ret) { /* handle lock acquisition */
> -			if (!silent)
> +			if (!params.silent)
>  				warn("thread %d: Could not lock pi-lock for %p (%d)",
>  				     w->tid, w->futex, ret);
>  			if (done)
> @@ -104,7 +118,7 @@ static void *workerfn(void *arg)
>  
>  		usleep(1);
>  		ret = futex_unlock_pi(w->futex, futex_flag);
> -		if (ret && !silent)
> +		if (ret && !params.silent)
>  			warn("thread %d: Could not unlock pi-lock for %p (%d)",
>  			     w->tid, w->futex, ret);
>  		ops++; /* account for thread's share of work */
> @@ -120,12 +134,12 @@ static void create_threads(struct worker *w, pthread_attr_t thread_attr,
>  	cpu_set_t cpuset;
>  	unsigned int i;
>  
> -	threads_starting = nthreads;
> +	threads_starting = params.nthreads;
>  
> -	for (i = 0; i < nthreads; i++) {
> +	for (i = 0; i < params.nthreads; i++) {
>  		worker[i].tid = i;
>  
> -		if (multi) {
> +		if (params.multi) {
>  			worker[i].futex = calloc(1, sizeof(u_int32_t));
>  			if (!worker[i].futex)
>  				err(EXIT_FAILURE, "calloc");
> @@ -164,25 +178,25 @@ int bench_futex_lock_pi(int argc, const char **argv)
>  	act.sa_sigaction = toggle_done;
>  	sigaction(SIGINT, &act, NULL);
>  
> -	if (!nthreads)
> -		nthreads = cpu->nr;
> +	if (!params.nthreads)
> +		params.nthreads = cpu->nr;
>  
> -	worker = calloc(nthreads, sizeof(*worker));
> +	worker = calloc(params.nthreads, sizeof(*worker));
>  	if (!worker)
>  		err(EXIT_FAILURE, "calloc");
>  
> -	if (!fshared)
> +	if (!params.fshared)
>  		futex_flag = FUTEX_PRIVATE_FLAG;
>  
>  	printf("Run summary [PID %d]: %d threads doing pi lock/unlock pairing for %d secs.\n\n",
> -	       getpid(), nthreads, nsecs);
> +	       getpid(), params.nthreads, params.runtime);
>  
>  	init_stats(&throughput_stats);
>  	pthread_mutex_init(&thread_lock, NULL);
>  	pthread_cond_init(&thread_parent, NULL);
>  	pthread_cond_init(&thread_worker, NULL);
>  
> -	threads_starting = nthreads;
> +	threads_starting = params.nthreads;
>  	pthread_attr_init(&thread_attr);
>  	gettimeofday(&bench__start, NULL);
>  
> @@ -195,10 +209,10 @@ int bench_futex_lock_pi(int argc, const char **argv)
>  	pthread_cond_broadcast(&thread_worker);
>  	pthread_mutex_unlock(&thread_lock);
>  
> -	sleep(nsecs);
> +	sleep(params.runtime);
>  	toggle_done(0, NULL, NULL);
>  
> -	for (i = 0; i < nthreads; i++) {
> +	for (i = 0; i < params.nthreads; i++) {
>  		ret = pthread_join(worker[i].thread, NULL);
>  		if (ret)
>  			err(EXIT_FAILURE, "pthread_join");
> @@ -209,16 +223,16 @@ int bench_futex_lock_pi(int argc, const char **argv)
>  	pthread_cond_destroy(&thread_worker);
>  	pthread_mutex_destroy(&thread_lock);
>  
> -	for (i = 0; i < nthreads; i++) {
> +	for (i = 0; i < params.nthreads; i++) {
>  		unsigned long t = bench__runtime.tv_sec > 0 ?
>  			worker[i].ops / bench__runtime.tv_sec : 0;
>  
>  		update_stats(&throughput_stats, t);
> -		if (!silent)
> +		if (!params.silent)
>  			printf("[thread %3d] futex: %p [ %ld ops/sec ]\n",
>  			       worker[i].tid, worker[i].futex, t);
>  
> -		if (multi)
> +		if (params.multi)
>  			zfree(&worker[i].futex);
>  	}
>  
> diff --git a/tools/perf/bench/futex-requeue.c b/tools/perf/bench/futex-requeue.c
> index 5fa23295ee5f..b65761e98245 100644
> --- a/tools/perf/bench/futex-requeue.c
> +++ b/tools/perf/bench/futex-requeue.c
> @@ -30,25 +30,38 @@
>  
>  static u_int32_t futex1 = 0, futex2 = 0;
>  
> -/*
> - * How many tasks to requeue at a time.
> - * Default to 1 in order to make the kernel work more.
> - */
> -static unsigned int nrequeue = 1;
> -
>  static pthread_t *worker;
> -static bool done = false, silent = false, fshared = false;
> +static bool done = 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 threads_starting, nthreads = 0;
> +static unsigned int threads_starting;
>  static int futex_flag = 0;
>  
> +struct parameters {
> +	unsigned int nthreads;
> +        unsigned int nrequeue;
> +	bool silent;
> +	bool fshared;
> +};
> +
> +static struct parameters params = {
> +	/*
> +	 * How many tasks to requeue at a time.
> +	 * Default to 1 in order to make the kernel work more.
> +	 */
> +	.nrequeue = 1,
> +};
> +
>  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', "silent",   &silent,   "Silent mode: do not display data/details"),
> -	OPT_BOOLEAN( 'S', "shared",   &fshared,  "Use shared futexes instead of private ones"),
> +	OPT_UINTEGER('t', "threads",  &params.nthreads,
> +		     "Specify amount of threads"),
> +	OPT_UINTEGER('q', "nrequeue", &params.nrequeue,
> +		     "Specify amount of threads to requeue at once"),
> +	OPT_BOOLEAN( 's', "silent",   &params.silent,
> +		     "Silent mode: do not display data/details"),
> +	OPT_BOOLEAN( 'S', "shared",   &params.fshared,
> +		     "Use shared futexes instead of private ones"),
>  	OPT_END()
>  };
>  
> @@ -65,7 +78,7 @@ static void print_summary(void)
>  
>  	printf("Requeued %d of %d threads in %.4f ms (+-%.2f%%)\n",
>  	       requeued_avg,
> -	       nthreads,
> +	       params.nthreads,
>  	       requeuetime_avg / USEC_PER_MSEC,
>  	       rel_stddev_stats(requeuetime_stddev, requeuetime_avg));
>  }
> @@ -89,10 +102,10 @@ static void block_threads(pthread_t *w,
>  	cpu_set_t cpuset;
>  	unsigned int i;
>  
> -	threads_starting = nthreads;
> +	threads_starting = params.nthreads;
>  
>  	/* create and block all threads */
> -	for (i = 0; i < nthreads; i++) {
> +	for (i = 0; i < params.nthreads; i++) {
>  		CPU_ZERO(&cpuset);
>  		CPU_SET(cpu->map[i % cpu->nr], &cpuset);
>  
> @@ -132,22 +145,22 @@ int bench_futex_requeue(int argc, const char **argv)
>  	act.sa_sigaction = toggle_done;
>  	sigaction(SIGINT, &act, NULL);
>  
> -	if (!nthreads)
> -		nthreads = cpu->nr;
> +	if (!params.nthreads)
> +		params.nthreads = cpu->nr;
>  
> -	worker = calloc(nthreads, sizeof(*worker));
> +	worker = calloc(params.nthreads, sizeof(*worker));
>  	if (!worker)
>  		err(EXIT_FAILURE, "calloc");
>  
> -	if (!fshared)
> +	if (!params.fshared)
>  		futex_flag = FUTEX_PRIVATE_FLAG;
>  
> -	if (nrequeue > nthreads)
> -		nrequeue = nthreads;
> +	if (params.nrequeue > params.nthreads)
> +		params.nrequeue = params.nthreads;
>  
>  	printf("Run summary [PID %d]: Requeuing %d threads (from [%s] %p to %p), "
> -	       "%d at a time.\n\n",  getpid(), nthreads,
> -	       fshared ? "shared":"private", &futex1, &futex2, nrequeue);
> +	       "%d at a time.\n\n",  getpid(), params.nthreads,
> +	       params.fshared ? "shared":"private", &futex1, &futex2, params.nrequeue);
>  
>  	init_stats(&requeued_stats);
>  	init_stats(&requeuetime_stats);
> @@ -174,13 +187,14 @@ int bench_futex_requeue(int argc, const char **argv)
>  
>  		/* Ok, all threads are patiently blocked, start requeueing */
>  		gettimeofday(&start, NULL);
> -		while (nrequeued < nthreads) {
> +		while (nrequeued < params.nthreads) {
>  			/*
>  			 * Do not wakeup any tasks blocked on futex1, allowing
>  			 * us to really measure futex_wait functionality.
>  			 */
>  			nrequeued += futex_cmp_requeue(&futex1, 0, &futex2, 0,
> -						       nrequeue, futex_flag);
> +						       params.nrequeue,
> +						       futex_flag);
>  		}
>  
>  		gettimeofday(&end, NULL);
> @@ -189,17 +203,19 @@ int bench_futex_requeue(int argc, const char **argv)
>  		update_stats(&requeued_stats, nrequeued);
>  		update_stats(&requeuetime_stats, runtime.tv_usec);
>  
> -		if (!silent) {
> +		if (!params.silent) {
>  			printf("[Run %d]: Requeued %d of %d threads in %.4f ms\n",
> -			       j + 1, nrequeued, nthreads, runtime.tv_usec / (double)USEC_PER_MSEC);
> +			       j + 1, nrequeued, params.nthreads,
> +			       runtime.tv_usec / (double)USEC_PER_MSEC);
>  		}
>  
>  		/* everybody should be blocked on futex2, wake'em up */
>  		nrequeued = futex_wake(&futex2, nrequeued, futex_flag);
> -		if (nthreads != nrequeued)
> -			warnx("couldn't wakeup all tasks (%d/%d)", nrequeued, nthreads);
> +		if (params.nthreads != nrequeued)
> +			warnx("couldn't wakeup all tasks (%d/%d)",
> +			      nrequeued, params.nthreads);
>  
> -		for (i = 0; i < nthreads; i++) {
> +		for (i = 0; i < params.nthreads; i++) {
>  			ret = pthread_join(worker[i], NULL);
>  			if (ret)
>  				err(EXIT_FAILURE, "pthread_join");
> diff --git a/tools/perf/bench/futex-wake-parallel.c b/tools/perf/bench/futex-wake-parallel.c
> index 6e6f5247e1fe..a80dfff5fe37 100644
> --- a/tools/perf/bench/futex-wake-parallel.c
> +++ b/tools/perf/bench/futex-wake-parallel.c
> @@ -47,8 +47,7 @@ static unsigned int nwakes = 1;
>  static u_int32_t futex = 0;
>  
>  static pthread_t *blocked_worker;
> -static bool done = false, silent = false, fshared = false;
> -static unsigned int nblocked_threads = 0, nwaking_threads = 0;
> +static bool done = false;
>  static pthread_mutex_t thread_lock;
>  static pthread_cond_t thread_parent, thread_worker;
>  static pthread_barrier_t barrier;
> @@ -56,11 +55,24 @@ static struct stats waketime_stats, wakeup_stats;
>  static unsigned int threads_starting;
>  static int futex_flag = 0;
>  
> +struct parameters {
> +	unsigned int nwaking_threads;
> +	unsigned int nblocked_threads;
> +	bool silent;
> +	bool fshared;
> +};
> +
> +static struct parameters params;
> +
>  static const struct option options[] = {
> -	OPT_UINTEGER('t', "threads", &nblocked_threads, "Specify amount of threads"),
> -	OPT_UINTEGER('w', "nwakers", &nwaking_threads, "Specify amount of waking threads"),
> -	OPT_BOOLEAN( 's', "silent",  &silent,   "Silent mode: do not display data/details"),
> -	OPT_BOOLEAN( 'S', "shared",  &fshared,  "Use shared futexes instead of private ones"),
> +	OPT_UINTEGER('t', "threads", &params.nblocked_threads,
> +		     "Specify amount of threads"),
> +	OPT_UINTEGER('w', "nwakers", &params.nwaking_threads,
> +		     "Specify amount of waking threads"),
> +	OPT_BOOLEAN( 's', "silent",  &params.silent,
> +		     "Silent mode: do not display data/details"),
> +	OPT_BOOLEAN( 'S', "shared",  &params.fshared,
> +		     "Use shared futexes instead of private ones"),
>  	OPT_END()
>  };
>  
> @@ -96,10 +108,10 @@ static void wakeup_threads(struct thread_data *td, pthread_attr_t thread_attr)
>  
>  	pthread_attr_setdetachstate(&thread_attr, PTHREAD_CREATE_JOINABLE);
>  
> -	pthread_barrier_init(&barrier, NULL, nwaking_threads + 1);
> +	pthread_barrier_init(&barrier, NULL, params.nwaking_threads + 1);
>  
>  	/* create and block all threads */
> -	for (i = 0; i < nwaking_threads; i++) {
> +	for (i = 0; i < params.nwaking_threads; i++) {
>  		/*
>  		 * Thread creation order will impact per-thread latency
>  		 * as it will affect the order to acquire the hb spinlock.
> @@ -112,7 +124,7 @@ static void wakeup_threads(struct thread_data *td, pthread_attr_t thread_attr)
>  
>  	pthread_barrier_wait(&barrier);
>  
> -	for (i = 0; i < nwaking_threads; i++)
> +	for (i = 0; i < params.nwaking_threads; i++)
>  		if (pthread_join(td[i].worker, NULL))
>  			err(EXIT_FAILURE, "pthread_join");
>  
> @@ -143,10 +155,10 @@ static void block_threads(pthread_t *w, pthread_attr_t thread_attr,
>  	cpu_set_t cpuset;
>  	unsigned int i;
>  
> -	threads_starting = nblocked_threads;
> +	threads_starting = params.nblocked_threads;
>  
>  	/* create and block all threads */
> -	for (i = 0; i < nblocked_threads; i++) {
> +	for (i = 0; i < params.nblocked_threads; i++) {
>  		CPU_ZERO(&cpuset);
>  		CPU_SET(cpu->map[i % cpu->nr], &cpuset);
>  
> @@ -167,7 +179,7 @@ static void print_run(struct thread_data *waking_worker, unsigned int run_num)
>  	init_stats(&__wakeup_stats);
>  	init_stats(&__waketime_stats);
>  
> -	for (i = 0; i < nwaking_threads; i++) {
> +	for (i = 0; i < params.nwaking_threads; i++) {
>  		update_stats(&__waketime_stats, waking_worker[i].runtime.tv_usec);
>  		update_stats(&__wakeup_stats, waking_worker[i].nwoken);
>  	}
> @@ -178,7 +190,7 @@ static void print_run(struct thread_data *waking_worker, unsigned int run_num)
>  
>  	printf("[Run %d]: Avg per-thread latency (waking %d/%d threads) "
>  	       "in %.4f ms (+-%.2f%%)\n", run_num + 1, wakeup_avg,
> -	       nblocked_threads, waketime_avg / USEC_PER_MSEC,
> +	       params.nblocked_threads, waketime_avg / USEC_PER_MSEC,
>  	       rel_stddev_stats(waketime_stddev, waketime_avg));
>  }
>  
> @@ -193,7 +205,7 @@ static void print_summary(void)
>  
>  	printf("Avg per-thread latency (waking %d/%d threads) in %.4f ms (+-%.2f%%)\n",
>  	       wakeup_avg,
> -	       nblocked_threads,
> +	       params.nblocked_threads,
>  	       waketime_avg / USEC_PER_MSEC,
>  	       rel_stddev_stats(waketime_stddev, waketime_avg));
>  }
> @@ -203,7 +215,7 @@ static void do_run_stats(struct thread_data *waking_worker)
>  {
>  	unsigned int i;
>  
> -	for (i = 0; i < nwaking_threads; i++) {
> +	for (i = 0; i < params.nwaking_threads; i++) {
>  		update_stats(&waketime_stats, waking_worker[i].runtime.tv_usec);
>  		update_stats(&wakeup_stats, waking_worker[i].nwoken);
>  	}
> @@ -242,32 +254,33 @@ int bench_futex_wake_parallel(int argc, const char **argv)
>  	if (!cpu)
>  		err(EXIT_FAILURE, "calloc");
>  
> -	if (!nblocked_threads)
> -		nblocked_threads = cpu->nr;
> +	if (!params.nblocked_threads)
> +		params.nblocked_threads = cpu->nr;
>  
>  	/* some sanity checks */
> -	if (nwaking_threads > nblocked_threads || !nwaking_threads)
> -		nwaking_threads = nblocked_threads;
> +	if (params.nwaking_threads > params.nblocked_threads ||
> +	    !params.nwaking_threads)
> +		params.nwaking_threads = params.nblocked_threads;
>  
> -	if (nblocked_threads % nwaking_threads)
> +	if (params.nblocked_threads % params.nwaking_threads)
>  		errx(EXIT_FAILURE, "Must be perfectly divisible");
>  	/*
>  	 * Each thread will wakeup nwakes tasks in
>  	 * a single futex_wait call.
>  	 */
> -	nwakes = nblocked_threads/nwaking_threads;
> +	nwakes = params.nblocked_threads/params.nwaking_threads;
>  
> -	blocked_worker = calloc(nblocked_threads, sizeof(*blocked_worker));
> +	blocked_worker = calloc(params.nblocked_threads, sizeof(*blocked_worker));
>  	if (!blocked_worker)
>  		err(EXIT_FAILURE, "calloc");
>  
> -	if (!fshared)
> +	if (!params.fshared)
>  		futex_flag = FUTEX_PRIVATE_FLAG;
>  
>  	printf("Run summary [PID %d]: blocking on %d threads (at [%s] "
>  	       "futex %p), %d threads waking up %d at a time.\n\n",
> -	       getpid(), nblocked_threads, fshared ? "shared":"private",
> -	       &futex, nwaking_threads, nwakes);
> +	       getpid(), params.nblocked_threads, params.fshared ? "shared":"private",
> +	       &futex, params.nwaking_threads, nwakes);
>  
>  	init_stats(&wakeup_stats);
>  	init_stats(&waketime_stats);
> @@ -278,7 +291,7 @@ int bench_futex_wake_parallel(int argc, const char **argv)
>  	pthread_cond_init(&thread_worker, NULL);
>  
>  	for (j = 0; j < bench_repeat && !done; j++) {
> -		waking_worker = calloc(nwaking_threads, sizeof(*waking_worker));
> +		waking_worker = calloc(params.nwaking_threads, sizeof(*waking_worker));
>  		if (!waking_worker)
>  			err(EXIT_FAILURE, "calloc");
>  
> @@ -297,14 +310,14 @@ int bench_futex_wake_parallel(int argc, const char **argv)
>  		/* Ok, all threads are patiently blocked, start waking folks up */
>  		wakeup_threads(waking_worker, thread_attr);
>  
> -		for (i = 0; i < nblocked_threads; i++) {
> +		for (i = 0; i < params.nblocked_threads; i++) {
>  			ret = pthread_join(blocked_worker[i], NULL);
>  			if (ret)
>  				err(EXIT_FAILURE, "pthread_join");
>  		}
>  
>  		do_run_stats(waking_worker);
> -		if (!silent)
> +		if (!params.silent)
>  			print_run(waking_worker, j);
>  
>  		free(waking_worker);
> diff --git a/tools/perf/bench/futex-wake.c b/tools/perf/bench/futex-wake.c
> index 6d217868f53c..22763774ede7 100644
> --- a/tools/perf/bench/futex-wake.c
> +++ b/tools/perf/bench/futex-wake.c
> @@ -31,25 +31,38 @@
>  /* all threads will block on the same futex */
>  static u_int32_t futex1 = 0;
>  
> -/*
> - * How many wakeups to do at a time.
> - * Default to 1 in order to make the kernel work more.
> - */
> -static unsigned int nwakes = 1;
> -
> -pthread_t *worker;
> -static bool done = false, silent = false, fshared = false;
> +static pthread_t *worker;
> +static bool done = 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 threads_starting, nthreads = 0;
> +static unsigned int threads_starting;
>  static int futex_flag = 0;
>  
> +struct parameters {
> +	unsigned int nthreads;
> +        unsigned int nwakes;
> +	bool silent;
> +	bool fshared;
> +};
> +
> +static struct parameters params = {
> +	/*
> +	 * How many wakeups to do at a time.
> +	 * Default to 1 in order to make the kernel work more.
> +	 */
> +	.nwakes  = 1,
> +};
> +
>  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', "silent",  &silent,   "Silent mode: do not display data/details"),
> -	OPT_BOOLEAN( 'S', "shared",  &fshared,  "Use shared futexes instead of private ones"),
> +	OPT_UINTEGER('t', "threads", &params.nthreads,
> +		     "Specify amount of threads"),
> +	OPT_UINTEGER('w', "nwakes",  &params.nwakes,
> +		     "Specify amount of threads to wake at once"),
> +	OPT_BOOLEAN( 's', "silent",  &params.silent,
> +		     "Silent mode: do not display data/details"),
> +	OPT_BOOLEAN( 'S', "shared",  &params.fshared,
> +		     "Use shared futexes instead of private ones"),
>  	OPT_END()
>  };
>  
> @@ -84,7 +97,7 @@ static void print_summary(void)
>  
>  	printf("Wokeup %d of %d threads in %.4f ms (+-%.2f%%)\n",
>  	       wakeup_avg,
> -	       nthreads,
> +	       params.nthreads,
>  	       waketime_avg / USEC_PER_MSEC,
>  	       rel_stddev_stats(waketime_stddev, waketime_avg));
>  }
> @@ -95,10 +108,10 @@ static void block_threads(pthread_t *w,
>  	cpu_set_t cpuset;
>  	unsigned int i;
>  
> -	threads_starting = nthreads;
> +	threads_starting = params.nthreads;
>  
>  	/* create and block all threads */
> -	for (i = 0; i < nthreads; i++) {
> +	for (i = 0; i < params.nthreads; i++) {
>  		CPU_ZERO(&cpuset);
>  		CPU_SET(cpu->map[i % cpu->nr], &cpuset);
>  
> @@ -140,19 +153,20 @@ int bench_futex_wake(int argc, const char **argv)
>  	act.sa_sigaction = toggle_done;
>  	sigaction(SIGINT, &act, NULL);
>  
> -	if (!nthreads)
> -		nthreads = cpu->nr;
> +	if (!params.nthreads)
> +		params.nthreads = cpu->nr;
>  
> -	worker = calloc(nthreads, sizeof(*worker));
> +	worker = calloc(params.nthreads, sizeof(*worker));
>  	if (!worker)
>  		err(EXIT_FAILURE, "calloc");
>  
> -	if (!fshared)
> +	if (!params.fshared)
>  		futex_flag = FUTEX_PRIVATE_FLAG;
>  
>  	printf("Run summary [PID %d]: blocking on %d threads (at [%s] futex %p), "
>  	       "waking up %d at a time.\n\n",
> -	       getpid(), nthreads, fshared ? "shared":"private",  &futex1, nwakes);
> +	       getpid(), params.nthreads, params.fshared ? "shared":"private",
> +	       &futex1, params.nwakes);
>  
>  	init_stats(&wakeup_stats);
>  	init_stats(&waketime_stats);
> @@ -179,20 +193,22 @@ 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_flag);
> +		while (nwoken != params.nthreads)
> +			nwoken += futex_wake(&futex1,
> +					     params.nwakes, futex_flag);
>  		gettimeofday(&end, NULL);
>  		timersub(&end, &start, &runtime);
>  
>  		update_stats(&wakeup_stats, nwoken);
>  		update_stats(&waketime_stats, runtime.tv_usec);
>  
> -		if (!silent) {
> +		if (!params.silent) {
>  			printf("[Run %d]: Wokeup %d of %d threads in %.4f ms\n",
> -			       j + 1, nwoken, nthreads, runtime.tv_usec / (double)USEC_PER_MSEC);
> +			       j + 1, nwoken, params.nthreads,
> +			       runtime.tv_usec / (double)USEC_PER_MSEC);
>  		}
>  
> -		for (i = 0; i < nthreads; i++) {
> +		for (i = 0; i < params.nthreads; i++) {
>  			ret = pthread_join(worker[i], NULL);
>  			if (ret)
>  				err(EXIT_FAILURE, "pthread_join");
> -- 
> 2.26.2
> 

-- 

- Arnaldo