Staging
v0.7.0
v0.7.0
https://github.com/torvalds/linux
Tip revision: af2d861d4cd2a4da5137f795ee3509e6f944a25b authored by Linus Torvalds on 24 April 2022, 21:51:22 UTC
Linux 5.18-rc4
Linux 5.18-rc4
Tip revision: af2d861
sched-pipe.c
// SPDX-License-Identifier: GPL-2.0
/*
*
* sched-pipe.c
*
* pipe: Benchmark for pipe()
*
* Based on pipe-test-1m.c by Ingo Molnar <mingo@redhat.com>
* http://people.redhat.com/mingo/cfs-scheduler/tools/pipe-test-1m.c
* Ported to perf by Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp>
*/
#include <subcmd/parse-options.h>
#include "bench.h"
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <sys/wait.h>
#include <string.h>
#include <errno.h>
#include <assert.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/syscall.h>
#include <linux/time64.h>
#include <pthread.h>
struct thread_data {
int nr;
int pipe_read;
int pipe_write;
pthread_t pthread;
};
#define LOOPS_DEFAULT 1000000
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_BOOLEAN('T', "threaded", &threaded, "Specify threads/process based task setup"),
OPT_END()
};
static const char * const bench_sched_pipe_usage[] = {
"perf bench sched pipe <options>",
NULL
};
static void *worker_thread(void *__tdata)
{
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)
{
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?
* discarding returned value of read(), write()
* causes error in building environment for perf
*/
int __maybe_unused ret, wait_stat;
pid_t pid, retpid __maybe_unused;
argc = parse_options(argc, argv, options, bench_sched_pipe_usage, 0);
BUG_ON(pipe(pipe_1));
BUG_ON(pipe(pipe_2));
gettimeofday(&start, NULL);
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 {
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);
switch (bench_format) {
case BENCH_FORMAT_DEFAULT:
printf("# Executed %d pipe operations between two %s\n\n",
loops, threaded ? "threads" : "processes");
result_usec = diff.tv_sec * USEC_PER_SEC;
result_usec += diff.tv_usec;
printf(" %14s: %lu.%03lu [sec]\n\n", "Total time",
(unsigned long) diff.tv_sec,
(unsigned long) (diff.tv_usec / USEC_PER_MSEC));
printf(" %14lf usecs/op\n",
(double)result_usec / (double)loops);
printf(" %14d ops/sec\n",
(int)((double)loops /
((double)result_usec / (double)USEC_PER_SEC)));
break;
case BENCH_FORMAT_SIMPLE:
printf("%lu.%03lu\n",
(unsigned long) diff.tv_sec,
(unsigned long) (diff.tv_usec / USEC_PER_MSEC));
break;
default:
/* reaching here is something disaster */
fprintf(stderr, "Unknown format:%d\n", bench_format);
exit(1);
break;
}
return 0;
}