Commit 32067712 authored by Kan Liang's avatar Kan Liang Committed by Arnaldo Carvalho de Melo
Browse files

perf tools: Per-event time support 

This patchkit adds the ability to turn off time stamps per event.

One usaful case for partial time is to work with per-event callgraph to
enable "PEBS threshold > 1" (https://lkml.org/lkml/2015/5/10/196

), which
can significantly reduce the sampling overhead.

The event samples with time stamps off will not be ordered.

Signed-off-by: default avatarKan Liang <kan.liang@intel.com>
Acked-by: default avatarJiri Olsa <jolsa@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/1438677022-34296-2-git-send-email-kan.liang@intel.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 34221118

tools/perf/Documentation/perf-record.txt

+3 −1
Original line number Diff line number Diff line
@@ -49,7 +49,9 @@ OPTIONS 
	  These params can be used to overload default config values per event.

	  Here is a list of the params.

	  - 'period': Set event sampling period



	  - 'time': Disable/enable time stamping. Acceptable values are 1 for

		    enabling time stamping. 0 for disabling time stamping.

		    The default is 1.

	  Note: If user explicitly sets options which conflict with the params,

	  the value set by the params will be overridden.

tools/perf/util/evsel.c

+11 −3
Original line number Diff line number Diff line
@@ -587,15 +587,23 @@ perf_evsel__config_callgraph(struct perf_evsel *evsel, 
	}

}



static void apply_config_terms(struct perf_event_attr *attr __maybe_unused,

			       struct list_head *config_terms)

static void apply_config_terms(struct perf_evsel *evsel)

{

	struct perf_evsel_config_term *term;

	struct list_head *config_terms = &evsel->config_terms;

	struct perf_event_attr *attr = &evsel->attr;



	list_for_each_entry(term, config_terms, list) {

		switch (term->type) {

		case PERF_EVSEL__CONFIG_TERM_PERIOD:

			attr->sample_period = term->val.period;

			break;

		case PERF_EVSEL__CONFIG_TERM_TIME:

			if (term->val.time)

				perf_evsel__set_sample_bit(evsel, TIME);

			else

				perf_evsel__reset_sample_bit(evsel, TIME);

			break;

		default:

			break;

		}
@@ -798,7 +806,7 @@ void perf_evsel__config(struct perf_evsel *evsel, struct record_opts *opts) 
	 * Apply event specific term settings,

	 * it overloads any global configuration.

	 */

	apply_config_terms(attr, &evsel->config_terms);

	apply_config_terms(evsel);

}



static int perf_evsel__alloc_fd(struct perf_evsel *evsel, int ncpus, int nthreads)

tools/perf/util/evsel.h

+2 −0
Original line number Diff line number Diff line
@@ -39,6 +39,7 @@ struct cgroup_sel; 
*/

enum {

	PERF_EVSEL__CONFIG_TERM_PERIOD,

	PERF_EVSEL__CONFIG_TERM_TIME,

	PERF_EVSEL__CONFIG_TERM_MAX,

};
@@ -47,6 +48,7 @@ struct perf_evsel_config_term { 
	int	type;

	union {

		u64	period;

		bool	time;

	} val;

};

tools/perf/util/parse-events.c

+12 −0
Original line number Diff line number Diff line
@@ -603,6 +603,14 @@ do { \ 
		 * attr->branch_sample_type = term->val.num;

		 */

		break;

	case PARSE_EVENTS__TERM_TYPE_TIME:

		CHECK_TYPE_VAL(NUM);

		if (term->val.num > 1) {

			err->str = strdup("expected 0 or 1");

			err->idx = term->err_val;

			return -EINVAL;

		}

		break;

	case PARSE_EVENTS__TERM_TYPE_NAME:

		CHECK_TYPE_VAL(STR);

		break;
@@ -650,6 +658,10 @@ do { \ 
		switch (term->type_term) {

		case PARSE_EVENTS__TERM_TYPE_SAMPLE_PERIOD:

			ADD_CONFIG_TERM(PERIOD, period, term->val.num);

			break;

		case PARSE_EVENTS__TERM_TYPE_TIME:

			ADD_CONFIG_TERM(TIME, time, term->val.num);

			break;

		default:

			break;

		}

tools/perf/util/parse-events.h

+1 −0
Original line number Diff line number Diff line
@@ -63,6 +63,7 @@ enum { 
	PARSE_EVENTS__TERM_TYPE_NAME,

	PARSE_EVENTS__TERM_TYPE_SAMPLE_PERIOD,

	PARSE_EVENTS__TERM_TYPE_BRANCH_SAMPLE_TYPE,

	PARSE_EVENTS__TERM_TYPE_TIME,

};



struct parse_events_term {

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