perf stat: extend -D,--delay option with -1 value

Extend -D,--delay option with -1 value to start monitoring with
events disabled to be enabled later by enable command provided
via control file descriptor.

Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/81ac633c-a844-5cfb-931c-820f6e6cbd12@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/Documentation/perf-stat.txt b/tools/perf/Documentation/perf-stat.txt
index b029ee7..9f32f6c 100644 (file)
--- a/tools/perf/Documentation/perf-stat.txt
+++ b/tools/perf/Documentation/perf-stat.txt
@@ -238,8 +238,9 @@ mode, use --per-node in addition to -a. (system-wide).
 
 -D msecs::
 --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.
+After starting the program, wait msecs before measuring (-1: start with events
+disabled). This is useful to filter out the startup phase of the program,
+which is often very different.
 
 -T::
 --transaction::

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index a5a0f48..9d5c503 100644 (file)
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -487,16 +487,26 @@ static bool handle_interval(unsigned int interval, int *times)
 
 static void enable_counters(void)
 {
-       if (stat_config.initial_delay)
+       if (stat_config.initial_delay < 0) {
+               pr_info(EVLIST_DISABLED_MSG);
+               return;
+       }
+
+       if (stat_config.initial_delay > 0) {
+               pr_info(EVLIST_DISABLED_MSG);
                usleep(stat_config.initial_delay * USEC_PER_MSEC);
+       }
 
        /*
         * We need to enable counters only if:
         * - we don't have tracee (attaching to task or cpu)
         * - we have initial delay configured
         */
-       if (!target__none(&target) || stat_config.initial_delay)
+       if (!target__none(&target) || stat_config.initial_delay) {
                evlist__enable(evsel_list);
+               if (stat_config.initial_delay > 0)
+                       pr_info(EVLIST_ENABLED_MSG);
+       }
 }
 
 static void disable_counters(void)
@@ -1053,8 +1063,8 @@ static struct option stat_options[] = {
                     "aggregate counts per thread", AGGR_THREAD),
        OPT_SET_UINT(0, "per-node", &stat_config.aggr_mode,
                     "aggregate counts per numa node", AGGR_NODE),
-       OPT_UINTEGER('D', "delay", &stat_config.initial_delay,
-                    "ms to wait before starting measurement after program start"),
+       OPT_INTEGER('D', "delay", &stat_config.initial_delay,
+                   "ms to wait before starting measurement after program start (-1: start with events disabled)"),
        OPT_CALLBACK_NOOPT(0, "metric-only", &stat_config.metric_only, NULL,
                        "Only print computed metrics. No raw values", enable_metric_only),
        OPT_BOOLEAN(0, "metric-no-group", &stat_config.metric_no_group,

diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
index ec676ac..c73f7f7 100644 (file)
--- a/tools/perf/util/evlist.h
+++ b/tools/perf/util/evlist.h
@@ -378,4 +378,7 @@ int evlist__finalize_ctlfd(struct evlist *evlist);
 bool evlist__ctlfd_initialized(struct evlist *evlist);
 int evlist__ctlfd_process(struct evlist *evlist, enum evlist_ctl_cmd *cmd);
 
+#define EVLIST_ENABLED_MSG "Events enabled\n"
+#define EVLIST_DISABLED_MSG "Events disabled\n"
+
 #endif /* __PERF_EVLIST_H */

diff --git a/tools/perf/util/stat.h b/tools/perf/util/stat.h
index 6911c72..41d59f1 100644 (file)
--- a/tools/perf/util/stat.h
+++ b/tools/perf/util/stat.h
@@ -116,7 +116,7 @@ struct perf_stat_config {
        FILE                    *output;
        unsigned int             interval;
        unsigned int             timeout;
-       unsigned int             initial_delay;
+       int                      initial_delay;
        unsigned int             unit_width;
        unsigned int             metric_only_len;
        int                      times;