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Ingo reported this small 'perf bench sched pipe' output problem: | $ ./perf bench sched pipe | (executing 1000000 pipe operations between two tasks) | | Total time:4.898 sec | $ 4.898586 usecs/op | 204140 ops/sec | | the shell prompt came back before the usecs/op and ops/sec line | was printed. Process teardown race, lack of wait() or so? This caused by lack of calling waitpid() by parent process, so I added it. Signed-off-by: Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jiri Kosina <jkosina@suse.cz> LKML-Reference: <1257737465-7546-1-git-send-email-mitake@dcl.info.waseda.ac.jp> Signed-off-by: Ingo Molnar <mingo@elte.hu>
118 lines
2.6 KiB
C
118 lines
2.6 KiB
C
/*
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*
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* builtin-bench-pipe.c
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*
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* pipe: Benchmark for pipe()
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*
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* Based on pipe-test-1m.c by Ingo Molnar <mingo@redhat.com>
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* http://people.redhat.com/mingo/cfs-scheduler/tools/pipe-test-1m.c
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* Ported to perf by Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp>
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*
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*/
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#include "../perf.h"
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#include "../util/util.h"
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#include "../util/parse-options.h"
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#include "../builtin.h"
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#include "bench.h"
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#include <unistd.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <signal.h>
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#include <sys/wait.h>
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#include <linux/unistd.h>
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#include <string.h>
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#include <errno.h>
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#include <assert.h>
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#include <sys/time.h>
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#include <sys/types.h>
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#define LOOPS_DEFAULT 1000000
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static int loops = LOOPS_DEFAULT;
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static int simple = 0;
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static const struct option options[] = {
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OPT_INTEGER('l', "loop", &loops,
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"Specify number of loops"),
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OPT_BOOLEAN('s', "simple-output", &simple,
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"Do simple output (this maybe useful for"
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"processing by scripts or graph tools like gnuplot)"),
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OPT_END()
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};
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static const char * const bench_sched_pipe_usage[] = {
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"perf bench sched pipe <options>",
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NULL
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};
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int bench_sched_pipe(int argc, const char **argv,
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const char *prefix __used)
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{
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int pipe_1[2], pipe_2[2];
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int m = 0, i;
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struct timeval start, stop, diff;
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unsigned long long result_usec = 0;
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/*
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* why does "ret" exist?
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* discarding returned value of read(), write()
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* causes error in building environment for perf
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*/
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int ret, wait_stat;
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pid_t pid, retpid;
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argc = parse_options(argc, argv, options,
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bench_sched_pipe_usage, 0);
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assert(!pipe(pipe_1));
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assert(!pipe(pipe_2));
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pid = fork();
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assert(pid >= 0);
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gettimeofday(&start, NULL);
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if (!pid) {
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for (i = 0; i < loops; i++) {
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ret = read(pipe_1[0], &m, sizeof(int));
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ret = write(pipe_2[1], &m, sizeof(int));
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}
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} else {
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for (i = 0; i < loops; i++) {
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ret = write(pipe_1[1], &m, sizeof(int));
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ret = read(pipe_2[0], &m, sizeof(int));
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}
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}
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gettimeofday(&stop, NULL);
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timersub(&stop, &start, &diff);
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if (pid) {
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retpid = waitpid(pid, &wait_stat, 0);
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assert((retpid == pid) && WIFEXITED(wait_stat));
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return 0;
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}
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if (simple)
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printf("%lu.%03lu\n",
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diff.tv_sec, diff.tv_usec / 1000);
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else {
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printf("(executing %d pipe operations between two tasks)\n\n",
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loops);
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result_usec = diff.tv_sec * 1000000;
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result_usec += diff.tv_usec;
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printf("\tTotal time:%lu.%03lu sec\n",
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diff.tv_sec, diff.tv_usec / 1000);
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printf("\t\t%lf usecs/op\n",
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(double)result_usec / (double)loops);
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printf("\t\t%d ops/sec\n",
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(int)((double)loops /
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((double)result_usec / (double)1000000)));
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}
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return 0;
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}
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