Commit b03b89b3 authored by Florian Fischer's avatar Florian Fischer Committed by Arnaldo Carvalho de Melo
Browse files

perf stat: Add user_time and system_time events 



It bothered me that during benchmarking using 'perf stat' (to collect
for example CPU cache events) I could not simultaneously retrieve the
times spend in user or kernel mode in a machine readable format.

When running 'perf stat' the output for humans contains the times
reported by rusage and wait4.

  $ perf stat -e cache-misses:u -- true

   Performance counter stats for 'true':

             4,206      cache-misses:u

       0.001113619 seconds time elapsed

       0.001175000 seconds user
       0.000000000 seconds sys

But 'perf stat's machine-readable format does not provide this information.

  $ perf stat -x, -e cache-misses:u -- true
  4282,,cache-misses:u,492859,100.00,,

I found no way to retrieve this information using the available events
while using machine-readable output.

This patch adds two new tool internal events 'user_time' and
'system_time', similarly to the already present 'duration_time' event.

Both events use the already collected rusage information obtained by
wait4 and tracked in the global ru_stats.

Examples presenting cache-misses and rusage information in both human
and machine-readable form:

  $ perf stat -e duration_time,user_time,system_time,cache-misses -- grep -q -r duration_time .

   Performance counter stats for 'grep -q -r duration_time .':

        67,422,542 ns   duration_time:u
        50,517,000 ns   user_time:u
        16,839,000 ns   system_time:u
            30,937      cache-misses:u

       0.067422542 seconds time elapsed

       0.050517000 seconds user
       0.016839000 seconds sys

  $ perf stat -x, -e duration_time,user_time,system_time,cache-misses -- grep -q -r duration_time .
  72134524,ns,duration_time:u,72134524,100.00,,
  65225000,ns,user_time:u,65225000,100.00,,
  6865000,ns,system_time:u,6865000,100.00,,
  38705,,cache-misses:u,71189328,100.00,,

Signed-off-by: default avatarFlorian Fischer <florian.fischer@muhq.space>
Tested-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Xing Zhengjun <zhengjun.xing@linux.intel.com>
Link: https://lore.kernel.org/r/20220420102354.468173-3-florian.fischer@muhq.space


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent c735b0a5

tools/perf/builtin-stat.c

+28 −8
Original line number Diff line number Diff line
@@ -342,7 +342,8 @@ static int evsel__write_stat_event(struct evsel *counter, int cpu_map_idx, u32 t 
static int read_single_counter(struct evsel *counter, int cpu_map_idx,

			       int thread, struct timespec *rs)

{

	if (counter->tool_event == PERF_TOOL_DURATION_TIME) {

	switch(counter->tool_event) {

		case PERF_TOOL_DURATION_TIME: {

			u64 val = rs->tv_nsec + rs->tv_sec*1000000000ULL;

			struct perf_counts_values *count =

				perf_counts(counter->counts, cpu_map_idx, thread);
@@ -350,7 +351,26 @@ static int read_single_counter(struct evsel *counter, int cpu_map_idx, 
			count->val = val;

			return 0;

		}

		case PERF_TOOL_USER_TIME:

		case PERF_TOOL_SYSTEM_TIME: {

			u64 val;

			struct perf_counts_values *count =

				perf_counts(counter->counts, cpu_map_idx, thread);

			if (counter->tool_event == PERF_TOOL_USER_TIME)

				val = ru_stats.ru_utime_usec_stat.mean;

			else

				val = ru_stats.ru_stime_usec_stat.mean;

			count->ena = count->run = val;

			count->val = val;

			return 0;

		}

		default:

		case PERF_TOOL_NONE:

			return evsel__read_counter(counter, cpu_map_idx, thread);

		case PERF_TOOL_MAX:

			/* This should never be reached */

			return 0;

	}

}



/*

tools/perf/util/evsel.h

+4 −0
Original line number Diff line number Diff line
@@ -30,6 +30,10 @@ typedef int (evsel__sb_cb_t)(union perf_event *event, void *data); 
enum perf_tool_event {

	PERF_TOOL_NONE		= 0,

	PERF_TOOL_DURATION_TIME = 1,

	PERF_TOOL_USER_TIME = 2,

	PERF_TOOL_SYSTEM_TIME = 3,



	PERF_TOOL_MAX,

};



/** struct evsel - event selector

tools/perf/util/parse-events.c

+3 −1
Original line number Diff line number Diff line
@@ -402,7 +402,9 @@ static int add_event_tool(struct list_head *list, int *idx, 
	if (!evsel)

		return -ENOMEM;

	evsel->tool_event = tool_event;

	if (tool_event == PERF_TOOL_DURATION_TIME) {

	if (tool_event == PERF_TOOL_DURATION_TIME

	    || tool_event == PERF_TOOL_USER_TIME

	    || tool_event == PERF_TOOL_SYSTEM_TIME) {

		free((char *)evsel->unit);

		evsel->unit = strdup("ns");

	}

tools/perf/util/parse-events.l

+2 −0
Original line number Diff line number Diff line
@@ -353,6 +353,8 @@ alignment-faults { return sym(yyscanner, PERF_TYPE_SOFTWARE, PERF_COUNT_SW_AL 
emulation-faults				{ return sym(yyscanner, PERF_TYPE_SOFTWARE, PERF_COUNT_SW_EMULATION_FAULTS); }

dummy						{ return sym(yyscanner, PERF_TYPE_SOFTWARE, PERF_COUNT_SW_DUMMY); }

duration_time					{ return tool(yyscanner, PERF_TOOL_DURATION_TIME); }

user_time						{ return tool(yyscanner, PERF_TOOL_USER_TIME); }

system_time						{ return tool(yyscanner, PERF_TOOL_SYSTEM_TIME); }

bpf-output					{ return sym(yyscanner, PERF_TYPE_SOFTWARE, PERF_COUNT_SW_BPF_OUTPUT); }

cgroup-switches					{ return sym(yyscanner, PERF_TYPE_SOFTWARE, PERF_COUNT_SW_CGROUP_SWITCHES); }