perf bench: Add sched-pipe.c: Benchmark for pipe() system call

This patch adds bench/sched-pipe.c.

bench/sched-pipe.c is a benchmark program
to measure performance of pipe() system call.
This benchmark is based on pipe-test-1m.c by Ingo Molnar:

   http://people.redhat.com/mingo/cfs-scheduler/tools/pipe-test-1m.c

Example of use:

% perf bench sched pipe
  (executing 1000000 pipe operations between two tasks)

          Total time:4.499 sec
                  4.499179 usecs/op
                  222262 ops/sec

% perf bench sched pipe -s -l 1000
0.015

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: Mike Galbraith <efault@gmx.de>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: fweisbec@gmail.com
Cc: Jiri Kosina <jkosina@suse.cz>
LKML-Reference: <1257381097-4743-4-git-send-email-mitake@dcl.info.waseda.ac.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 113 insertions, 0 deletions

diff --git a/tools/perf/bench/sched-pipe.c b/tools/perf/bench/sched-pipe.c
new file mode 100644
index 000000000000..3214ed20b1aa
--- /dev/null
+++ b/tools/perf/bench/sched-pipe.c
@@ -0,0 +1,113 @@
+/*
+ *
+ * builtin-bench-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 "../perf.h"
+#include "../util/util.h"
+#include "../util/parse-options.h"
+#include "../builtin.h"
+#include "bench.h"
+
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <sys/wait.h>
+#include <linux/unistd.h>
+#include <string.h>
+#include <errno.h>
+#include <assert.h>
+#include <sys/time.h>
+
+#define LOOPS_DEFAULT 1000000
+static int loops = LOOPS_DEFAULT;
+static int simple = 0;
+
+static const struct option options[] = {
+        OPT_INTEGER('l', "loop", &loops,
+                    "Specify number of loops"),
+        OPT_BOOLEAN('s', "simple-output", &simple,
+                    "Do simple output (this maybe useful for"
+                    "processing by scripts or graph tools like gnuplot)"),
+        OPT_END()
+};
+
+static const char * const bench_sched_pipe_usage[] = {
+        "perf bench sched pipe <options>",
+        NULL
+};
+
+int bench_sched_pipe(int argc, const char **argv,
+                     const char *prefix __used)
+{
+        int pipe_1[2], pipe_2[2];
+        int m = 0, i;
+        struct timeval start, stop, diff;
+        unsigned long long result_usec = 0;
+
+        /*
+         * why does "ret" exist?
+         * discarding returned value of read(), write()
+         * causes error in building environment for perf
+         */
+        int ret;
+        pid_t pid;
+
+        argc = parse_options(argc, argv, options,
+                             bench_sched_pipe_usage, 0);
+
+        assert(!pipe(pipe_1));
+        assert(!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));
+                }
+        } else {
+                for (i = 0; i < loops; i++) {
+                        ret = write(pipe_1[1], &m, sizeof(int));
+                        ret = read(pipe_2[0], &m, sizeof(int));
+                }
+        }
+
+        gettimeofday(&stop, NULL);
+        timersub(&stop, &start, &diff);
+
+        if (pid)
+                return 0;
+
+        if (simple)
+                printf("%lu.%03lu\n",
+                       diff.tv_sec, diff.tv_usec / 1000);
+        else {
+                printf("(executing %d pipe operations between two tasks)\n\n",
+                        loops);
+
+                result_usec = diff.tv_sec * 1000000;
+                result_usec += diff.tv_usec;
+
+                printf("\tTotal time:%lu.%03lu sec\n",
+                       diff.tv_sec, diff.tv_usec / 1000);
+                printf("\t\t%lf usecs/op\n",
+                       (double)result_usec / (double)loops);
+                printf("\t\t%d ops/sec\n",
+                       (int)((double)loops /
+                             ((double)result_usec / (double)1000000)));
+        }
+
+        return 0;
+}