[PATCH v2 04/11] perf stat: extend -D,--delay option with -1 value

Alexey Budankov
2020-05-06T18:20:59Z

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>
---
tools/perf/builtin-stat.c | 18 ++++++++++++++----
tools/perf/util/evlist.h | 3 +++
tools/perf/util/stat.h | 2 +-
3 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 9775b0905146..bda777ca0420 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -383,16 +383,26 @@ static bool print_interval_and_stop(struct perf_stat_config *config, int *times)

static void enable_counters(void)
{
- if (stat_config.initial_delay)
+ if (stat_config.initial_delay < 0) {
+ pr_info(PERF_EVLIST__DISABLED_MSG);
+ return;
+ }
+
+ if (stat_config.initial_delay > 0) {
+ pr_info(PERF_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(PERF_EVLIST__ENABLED_MSG);
+ }
}

static void disable_counters(void)
@@ -929,8 +939,8 @@ 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, "topdown", &topdown_run,
diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
index 84386850c290..874ecf068ac9 100644
--- a/tools/perf/util/evlist.h
+++ b/tools/perf/util/evlist.h
@@ -366,6 +366,9 @@ enum evlist_ctl_cmd {
CTL_CMD_ACK = 'a'
};

+#define PERF_EVLIST__ENABLED_MSG "Events enabled\n"
+#define PERF_EVLIST__DISABLED_MSG "Events disabled\n"
+
int perf_evlist__initialize_ctlfd(struct evlist *evlist, int ctl_fd, int ctl_fd_ack);
int perf_evlist__finalize_ctlfd(struct evlist *evlist);
int perf_evlist__ctlfd_process(struct evlist *evlist, enum evlist_ctl_cmd *cmd);
diff --git a/tools/perf/util/stat.h b/tools/perf/util/stat.h
index b4fdfaa7f2c0..027b9dcd902f 100644
--- a/tools/perf/util/stat.h
+++ b/tools/perf/util/stat.h
@@ -113,7 +113,7 @@ 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;
--
2.24.1