perf bench futex, requeue: Add --broadcast option

Such that all threads are requeued to uaddr2 in a single
futex_cmp_requeue(), unlike the default, which is 1.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lore.kernel.org/lkml/20210809043301.66002-6-dave@stgolabs.net
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/bench/futex-requeue.c

@@ -53,6 +53,7 @@ static const struct option options[] = {
 	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_BOOLEAN( 'm', "mlockall", &params.mlockall, "Lock all current and future memory"),
+	OPT_BOOLEAN( 'B', "broadcast", &params.broadcast, "Requeue all threads at once"),
 	OPT_END()
 };
 
@@ -154,6 +155,9 @@ int bench_futex_requeue(int argc, const char **argv)
 	if (params.nrequeue > params.nthreads)
 		params.nrequeue = params.nthreads;
 
+	if (params.broadcast)
+		params.nrequeue = params.nthreads;
+
 	printf("Run summary [PID %d]: Requeuing %d threads (from [%s] %p to %p), "
 	       "%d at a time.\n\n",  getpid(), params.nthreads,
 	       params.fshared ? "shared":"private", &futex1, &futex2, params.nrequeue);

tools/perf/bench/futex.h

@@ -18,6 +18,7 @@ struct bench_futex_parameters {
 	bool fshared;
 	bool mlockall;
 	bool multi; /* lock-pi */
+	bool broadcast; /* requeue */
 	unsigned int runtime; /* seconds*/
 	unsigned int nthreads;
 	unsigned int nfutexes;