perf record: Add --initial-delay option

perf stat has a --delay option to delay measuring the workload.

This is useful to skip measuring the startup phase of the program, which
is often very different from the main workload.

The same is useful for perf record when sampling.

--no-delay was already taken, so add a --initial-delay
to perf record too.
-D was already taken for record, so there is only a long option.

v2: Don't disable group members (Namhyung Kim)
v3: port to latest perf/core
    rename to --initial-delay to avoid conflict with --no-delay

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/1389476307-2124-1-git-send-email-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt
index c407897f04359c9e253fbcb27368926419aced51..82bffac036e1d95e792e13fda38bb4c73a43e5b0 100644 (file)
--- a/tools/perf/Documentation/perf-record.txt
+++ b/tools/perf/Documentation/perf-record.txt
@@ -209,6 +209,10 @@ overrides that and uses per-thread mmaps.  A side-effect of that is that
 inheritance is automatically disabled.  --per-thread is ignored with a warning
 if combined with -a or -C options.
 
+--initial-delay msecs::
+After starting the program, wait msecs before measuring. This is useful to
+filter out the startup phase of the program, which is often very different.
+
 SEE ALSO
 --------
 linkperf:perf-stat[1], linkperf:perf-list[1]

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 88600158400ef005d471eaa6d53789600275a9d3..07d4cf8d3fd3058f184209a170aa64512c18c1e2 100644 (file)
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -499,7 +499,7 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
         * (apart from group members) have enable_on_exec=1 set,
         * so don't spoil it by prematurely enabling them.
         */
-       if (!target__none(&opts->target))
+       if (!target__none(&opts->target) && !opts->initial_delay)
                perf_evlist__enable(rec->evlist);
 
        /*
@@ -508,6 +508,11 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
        if (forks)
                perf_evlist__start_workload(rec->evlist);
 
+       if (opts->initial_delay) {
+               usleep(opts->initial_delay * 1000);
+               perf_evlist__enable(rec->evlist);
+       }
+
        for (;;) {
                int hits = rec->samples;
 
@@ -877,6 +882,8 @@ const struct option record_options[] = {
        OPT_CALLBACK('G', "cgroup", &record.evlist, "name",
                     "monitor event in cgroup name only",
                     parse_cgroups),
+       OPT_UINTEGER(0, "initial-delay", &record.opts.initial_delay,
+                 "ms to wait before starting measurement after program start"),
        OPT_STRING('u', "uid", &record.opts.target.uid_str, "user",
                   "user to profile"),
 

diff --git a/tools/perf/perf.h b/tools/perf/perf.h
index b1cc84b01d5b935a77c0c492d50b5a1a1d8e54b5..af1ce6e14a934b1b1a3d8f4eb2d03707c4d511a0 100644 (file)
--- a/tools/perf/perf.h
+++ b/tools/perf/perf.h
@@ -269,6 +269,7 @@ struct record_opts {
        u64          user_interval;
        u16          stack_dump_size;
        bool         sample_transaction;
+       unsigned     initial_delay;
 };
 
 #endif

diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index ade8d9c1c43135688717214c48bb93f1a1556c28..cd4630abfa4362ad5b19314b965accc8820fab54 100644 (file)
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -658,7 +658,8 @@ void perf_evsel__config(struct perf_evsel *evsel, struct record_opts *opts)
         * Setting enable_on_exec for independent events and
         * group leaders for traced executed by perf.
         */
-       if (target__none(&opts->target) && perf_evsel__is_group_leader(evsel))
+       if (target__none(&opts->target) && perf_evsel__is_group_leader(evsel) &&
+               !opts->initial_delay)
                attr->enable_on_exec = 1;
 }