perf/bench/futex-requeue.c

1 // SPDX-License-Identifier: GPL-2.0
5  * futex-requeue: Block a bunch of threads on futex1 and requeue them
8  * This program is particularly useful to measure the latency of nthread
9  * requeues without waking up any tasks -- thus mimicking a regular futex_wait.
18 #include <subcmd/parse-options.h>
67 	printf("Requeued %d of %d threads in %.4f ms (+-%.2f%%)\n",  in print_summary()
77 	threads_starting--;  in workerfn()
98 		CPU_SET(cpu->map[i % cpu->nr], &cpuset);  in block_threads()
137 		nthreads = cpu->nr;  in bench_futex_requeue()
180 			 * Do not wakeup any tasks blocked on futex1, allowing  in bench_futex_requeue()
181 			 * us to really measure futex_wait functionality.  in bench_futex_requeue()
201 			warnx("couldn't wakeup all tasks (%d/%d)", nrequeued, nthreads);  in bench_futex_requeue()