perf/bench/futex-wake-parallel.c

1 // SPDX-License-Identifier: GPL-2.0
5  * Block a bunch of threads and let parallel waker threads wakeup an
27 #include <subcmd/parse-options.h>
47 /* all threads will block on the same futex -- hash bucket chaos ;) */
61 	OPT_UINTEGER('t', "threads", &nblocked_threads, "Specify amount of threads"),
62 	OPT_UINTEGER('w', "nwakers", &nwaking_threads, "Specify amount of waking threads"),
69 	"perf bench futex wake-parallel <options>",
82 	waker->nwoken = futex_wake(&futex, nwakes, futex_flag);  in waking_workerfn()
83 	if (waker->nwoken != nwakes)  in waking_workerfn()
85 		      waker->nwoken, nwakes);  in waking_workerfn()
88 	timersub(&end, &start, &waker->runtime);  in waking_workerfn()
102 	/* create and block all threads */  in wakeup_threads()
105 		 * Thread creation order will impact per-thread latency  in wakeup_threads()
126 	threads_starting--;  in blocked_workerfn()
149 	/* create and block all threads */  in block_threads()
152 		CPU_SET(cpu->map[i % cpu->nr], &cpuset);  in block_threads()
180 	printf("[Run %d]: Avg per-thread latency (waking %d/%d threads) "  in print_run()
181 	       "in %.4f ms (+-%.2f%%)\n", run_num + 1, wakeup_avg,  in print_run()
195 	printf("Avg per-thread latency (waking %d/%d threads) in %.4f ms (+-%.2f%%)\n",  in print_summary()
247 		nblocked_threads = cpu->nr;  in bench_futex_wake_parallel()
268 	printf("Run summary [PID %d]: blocking on %d threads (at [%s] "  in bench_futex_wake_parallel()
269 	       "futex %p), %d threads waking up %d at a time.\n\n",  in bench_futex_wake_parallel()
286 		/* create, launch & block all threads */  in bench_futex_wake_parallel()
289 		/* make sure all threads are already blocked */  in bench_futex_wake_parallel()
298 		/* Ok, all threads are patiently blocked, start waking folks up */  in bench_futex_wake_parallel()