perf record: Support per-event freq term

Now perf can set per-event value of time and (sampling) period.  But I
guess most users like me just want to set frequency rather than period.
So add the 'freq' term in the event parser.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1439102724-14079-1-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/Documentation/perf-record.txt

@@ -49,6 +49,7 @@ 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
+	  - 'freq': Set event sampling frequency
 	  - 'time': Disable/enable time stamping. Acceptable values are 1 for
 		    enabling time stamping. 0 for disabling time stamping.
 		    The default is 1.

tools/perf/util/evsel.c

@@ -600,6 +600,10 @@ static void apply_config_terms(struct perf_evsel *evsel)
 			attr->sample_period = term->val.period;
 			attr->freq = 0;
 			break;
+		case PERF_EVSEL__CONFIG_TERM_FREQ:
+			attr->sample_freq = term->val.freq;
+			attr->freq = 1;
+			break;
 		case PERF_EVSEL__CONFIG_TERM_TIME:
 			if (term->val.time)
 				perf_evsel__set_sample_bit(evsel, TIME);

tools/perf/util/evsel.h

@@ -39,6 +39,7 @@ struct cgroup_sel;
 */
 enum {
 	PERF_EVSEL__CONFIG_TERM_PERIOD,
+	PERF_EVSEL__CONFIG_TERM_FREQ,
 	PERF_EVSEL__CONFIG_TERM_TIME,
 	PERF_EVSEL__CONFIG_TERM_MAX,
 };
@@ -48,6 +49,7 @@ struct perf_evsel_config_term {
 	int	type;
 	union {
 		u64	period;
+		u64	freq;
 		bool	time;
 	} val;
 };

tools/perf/util/parse-events.c

@@ -597,6 +597,9 @@ do {									   \
 	case PARSE_EVENTS__TERM_TYPE_SAMPLE_PERIOD:
 		CHECK_TYPE_VAL(NUM);
 		break;
+	case PARSE_EVENTS__TERM_TYPE_SAMPLE_FREQ:
+		CHECK_TYPE_VAL(NUM);
+		break;
 	case PARSE_EVENTS__TERM_TYPE_BRANCH_SAMPLE_TYPE:
 		/*
 		 * TODO uncomment when the field is available
@@ -659,6 +662,9 @@ do {								\
 		case PARSE_EVENTS__TERM_TYPE_SAMPLE_PERIOD:
 			ADD_CONFIG_TERM(PERIOD, period, term->val.num);
 			break;
+		case PARSE_EVENTS__TERM_TYPE_SAMPLE_FREQ:
+			ADD_CONFIG_TERM(FREQ, freq, term->val.num);
+			break;
 		case PARSE_EVENTS__TERM_TYPE_TIME:
 			ADD_CONFIG_TERM(TIME, time, term->val.num);
 			break;

tools/perf/util/parse-events.h

@@ -62,6 +62,7 @@ enum {
 	PARSE_EVENTS__TERM_TYPE_CONFIG2,
 	PARSE_EVENTS__TERM_TYPE_NAME,
 	PARSE_EVENTS__TERM_TYPE_SAMPLE_PERIOD,
+	PARSE_EVENTS__TERM_TYPE_SAMPLE_FREQ,
 	PARSE_EVENTS__TERM_TYPE_BRANCH_SAMPLE_TYPE,
 	PARSE_EVENTS__TERM_TYPE_TIME,
 };

tools/perf/util/parse-events.l

@@ -182,6 +182,7 @@ config1			{ return term(yyscanner, PARSE_EVENTS__TERM_TYPE_CONFIG1); }
 config2			{ return term(yyscanner, PARSE_EVENTS__TERM_TYPE_CONFIG2); }
 name			{ return term(yyscanner, PARSE_EVENTS__TERM_TYPE_NAME); }
 period			{ return term(yyscanner, PARSE_EVENTS__TERM_TYPE_SAMPLE_PERIOD); }
+freq			{ return term(yyscanner, PARSE_EVENTS__TERM_TYPE_SAMPLE_FREQ); }
 branch_type		{ return term(yyscanner, PARSE_EVENTS__TERM_TYPE_BRANCH_SAMPLE_TYPE); }
 time			{ return term(yyscanner, PARSE_EVENTS__TERM_TYPE_TIME); }
 ,			{ return ','; }

tools/perf/util/pmu.c

@@ -634,7 +634,7 @@ static char *formats_error_string(struct list_head *formats)
 {
 	struct perf_pmu_format *format;
 	char *err, *str;
-	static const char *static_terms = "config,config1,config2,name,period,branch_type,time\n";
+	static const char *static_terms = "config,config1,config2,name,period,freq,branch_type,time\n";
 	unsigned i = 0;
 
 	if (!asprintf(&str, "valid terms:"))