From a9faa0cab619fad380c2669825aa84212943d528 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Mon, 23 Sep 2013 10:17:35 +0200 Subject: [PATCH] perf bench sched: Add --threaded option Allow the measurement of thread versus process context switch performance. The default stays at 'process' based measurement, like lmbench's lat_ctx benchmark. Sample output: comet:~/tip/tools/perf> taskset 1 ./perf bench sched pipe # Running sched/pipe benchmark... # Executed 1000000 pipe operations between two processes Total time: 4.138 [sec] 4.138729 usecs/op 241620 ops/sec comet:~/tip/tools/perf> taskset 1 ./perf bench sched pipe --threaded # Running sched/pipe benchmark... # Executed 1000000 pipe operations between two threads Total time: 3.667 [sec] 3.667667 usecs/op 272652 ops/sec Signed-off-by: Ingo Molnar Cc: Peter Zijlstra Cc: Namhyung Kim Cc: Jiri Olsa Cc: Arnaldo Carvalho de Melo Link: http://lkml.kernel.org/r/20130917114256.GA31159@gmail.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/bench/sched-pipe.c | 115 +++++++++++++++++++++++++--------- 1 file changed, 86 insertions(+), 29 deletions(-) diff --git a/tools/perf/bench/sched-pipe.c b/tools/perf/bench/sched-pipe.c index 69cfba8d4c6c..07a8d7646a15 100644 --- a/tools/perf/bench/sched-pipe.c +++ b/tools/perf/bench/sched-pipe.c @@ -7,9 +7,7 @@ * Based on pipe-test-1m.c by Ingo Molnar * http://people.redhat.com/mingo/cfs-scheduler/tools/pipe-test-1m.c * Ported to perf by Hitoshi Mitake - * */ - #include "../perf.h" #include "../util/util.h" #include "../util/parse-options.h" @@ -28,12 +26,24 @@ #include #include +#include + +struct thread_data { + int nr; + int pipe_read; + int pipe_write; + pthread_t pthread; +}; + #define LOOPS_DEFAULT 1000000 -static int loops = LOOPS_DEFAULT; +static int loops = LOOPS_DEFAULT; + +/* Use processes by default: */ +static bool threaded; static const struct option options[] = { - OPT_INTEGER('l', "loop", &loops, - "Specify number of loops"), + OPT_INTEGER('l', "loop", &loops, "Specify number of loops"), + OPT_BOOLEAN('T', "threaded", &threaded, "Specify threads/process based task setup"), OPT_END() }; @@ -42,13 +52,37 @@ static const char * const bench_sched_pipe_usage[] = { NULL }; -int bench_sched_pipe(int argc, const char **argv, - const char *prefix __maybe_unused) +static void *worker_thread(void *__tdata) { - int pipe_1[2], pipe_2[2]; + struct thread_data *td = __tdata; int m = 0, i; + int ret; + + for (i = 0; i < loops; i++) { + if (!td->nr) { + ret = read(td->pipe_read, &m, sizeof(int)); + BUG_ON(ret != sizeof(int)); + ret = write(td->pipe_write, &m, sizeof(int)); + BUG_ON(ret != sizeof(int)); + } else { + ret = write(td->pipe_write, &m, sizeof(int)); + BUG_ON(ret != sizeof(int)); + ret = read(td->pipe_read, &m, sizeof(int)); + BUG_ON(ret != sizeof(int)); + } + } + + return NULL; +} + +int bench_sched_pipe(int argc, const char **argv, const char *prefix __maybe_unused) +{ + struct thread_data threads[2], *td; + int pipe_1[2], pipe_2[2]; struct timeval start, stop, diff; unsigned long long result_usec = 0; + int nr_threads = 2; + int t; /* * why does "ret" exist? @@ -58,43 +92,66 @@ int bench_sched_pipe(int argc, const char **argv, int __maybe_unused ret, wait_stat; pid_t pid, retpid __maybe_unused; - argc = parse_options(argc, argv, options, - bench_sched_pipe_usage, 0); + argc = parse_options(argc, argv, options, bench_sched_pipe_usage, 0); BUG_ON(pipe(pipe_1)); BUG_ON(pipe(pipe_2)); - pid = fork(); - assert(pid >= 0); - gettimeofday(&start, NULL); - if (!pid) { - for (i = 0; i < loops; i++) { - ret = read(pipe_1[0], &m, sizeof(int)); - ret = write(pipe_2[1], &m, sizeof(int)); + for (t = 0; t < nr_threads; t++) { + td = threads + t; + + td->nr = t; + + if (t == 0) { + td->pipe_read = pipe_1[0]; + td->pipe_write = pipe_2[1]; + } else { + td->pipe_write = pipe_1[1]; + td->pipe_read = pipe_2[0]; } + } + + + if (threaded) { + + for (t = 0; t < nr_threads; t++) { + td = threads + t; + + ret = pthread_create(&td->pthread, NULL, worker_thread, td); + BUG_ON(ret); + } + + for (t = 0; t < nr_threads; t++) { + td = threads + t; + + ret = pthread_join(td->pthread, NULL); + BUG_ON(ret); + } + } else { - for (i = 0; i < loops; i++) { - ret = write(pipe_1[1], &m, sizeof(int)); - ret = read(pipe_2[0], &m, sizeof(int)); + pid = fork(); + assert(pid >= 0); + + if (!pid) { + worker_thread(threads + 0); + exit(0); + } else { + worker_thread(threads + 1); } + + retpid = waitpid(pid, &wait_stat, 0); + assert((retpid == pid) && WIFEXITED(wait_stat)); } gettimeofday(&stop, NULL); timersub(&stop, &start, &diff); - if (pid) { - retpid = waitpid(pid, &wait_stat, 0); - assert((retpid == pid) && WIFEXITED(wait_stat)); - } else { - exit(0); - } - switch (bench_format) { case BENCH_FORMAT_DEFAULT: - printf("# Executed %d pipe operations between two tasks\n\n", - loops); + printf("# Executed %d pipe operations between two %s\n\n", + loops, threaded ? "threads" : "processes"); result_usec = diff.tv_sec * 1000000; result_usec += diff.tv_usec;