perf record: Add aux-sample-size config term

To allow individual events to be selected for AUX area sampling, add
aux-sample-size config term. attr.aux_sample_size is updated by
auxtrace_parse_sample_options() so that the existing validation will see
the value. Any event that has a non-zero aux_sample_size will cause AUX
area sampling to be configured, irrespective of the --aux-sample option.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lore.kernel.org/lkml/20191115124225.5247-8-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/Documentation/perf-record.txt

@@ -62,6 +62,9 @@ OPTIONS
 		    like this: name=\'CPU_CLK_UNHALTED.THREAD:cmask=0x1\'.
 	  - 'aux-output': Generate AUX records instead of events. This requires
 			  that an AUX area event is also provided.
+	  - 'aux-sample-size': Set sample size for AUX area sampling. If the
+	  '--aux-sample' option has been used, set aux-sample-size=0 to disable
+	  AUX area sampling for the event.
 
           See the linkperf:perf-list[1] man page for more parameters.
 

tools/perf/util/auxtrace.c

@@ -31,6 +31,7 @@
 #include "map.h"
 #include "pmu.h"
 #include "evsel.h"
+#include "evsel_config.h"
 #include "symbol.h"
 #include "util/synthetic-events.h"
 #include "thread_map.h"
@@ -76,6 +77,53 @@ static bool perf_evsel__is_aux_event(struct evsel *evsel)
 	return pmu && pmu->auxtrace;
 }
 
+/*
+ * Make a group from 'leader' to 'last', requiring that the events were not
+ * already grouped to a different leader.
+ */
+static int perf_evlist__regroup(struct evlist *evlist,
+				struct evsel *leader,
+				struct evsel *last)
+{
+	struct evsel *evsel;
+	bool grp;
+
+	if (!perf_evsel__is_group_leader(leader))
+		return -EINVAL;
+
+	grp = false;
+	evlist__for_each_entry(evlist, evsel) {
+		if (grp) {
+			if (!(evsel->leader == leader ||
+			     (evsel->leader == evsel &&
+			      evsel->core.nr_members <= 1)))
+				return -EINVAL;
+		} else if (evsel == leader) {
+			grp = true;
+		}
+		if (evsel == last)
+			break;
+	}
+
+	grp = false;
+	evlist__for_each_entry(evlist, evsel) {
+		if (grp) {
+			if (evsel->leader != leader) {
+				evsel->leader = leader;
+				if (leader->core.nr_members < 1)
+					leader->core.nr_members = 1;
+				leader->core.nr_members += 1;
+			}
+		} else if (evsel == leader) {
+			grp = true;
+		}
+		if (evsel == last)
+			break;
+	}
+
+	return 0;
+}
+
 static bool auxtrace__dont_decode(struct perf_session *session)
 {
 	return !session->itrace_synth_opts ||
@@ -679,13 +727,16 @@ int auxtrace_parse_sample_options(struct auxtrace_record *itr,
 				  struct evlist *evlist,
 				  struct record_opts *opts, const char *str)
 {
+	struct perf_evsel_config_term *term;
+	struct evsel *aux_evsel;
+	bool has_aux_sample_size = false;
 	bool has_aux_leader = false;
 	struct evsel *evsel;
 	char *endptr;
 	unsigned long sz;
 
 	if (!str)
-		return 0;
+		goto no_opt;
 
 	if (!itr) {
 		pr_err("No AUX area event to sample\n");
@@ -712,6 +763,29 @@ int auxtrace_parse_sample_options(struct auxtrace_record *itr,
 			evsel->core.attr.aux_sample_size = sz;
 		}
 	}
+no_opt:
+	aux_evsel = NULL;
+	/* Override with aux_sample_size from config term */
+	evlist__for_each_entry(evlist, evsel) {
+		if (perf_evsel__is_aux_event(evsel))
+			aux_evsel = evsel;
+		term = perf_evsel__get_config_term(evsel, AUX_SAMPLE_SIZE);
+		if (term) {
+			has_aux_sample_size = true;
+			evsel->core.attr.aux_sample_size = term->val.aux_sample_size;
+			/* If possible, group with the AUX event */
+			if (aux_evsel && evsel->core.attr.aux_sample_size)
+				perf_evlist__regroup(evlist, aux_evsel, evsel);
+		}
+	}
+
+	if (!str && !has_aux_sample_size)
+		return 0;
+
+	if (!itr) {
+		pr_err("No AUX area event to sample\n");
+		return -EINVAL;
+	}
 
 	return auxtrace_validate_aux_sample_size(evlist, opts);
 }

tools/perf/util/evsel.c

@@ -846,6 +846,9 @@ static void apply_config_terms(struct evsel *evsel,
 		case PERF_EVSEL__CONFIG_TERM_AUX_OUTPUT:
 			attr->aux_output = term->val.aux_output ? 1 : 0;
 			break;
+		case PERF_EVSEL__CONFIG_TERM_AUX_SAMPLE_SIZE:
+			/* Already applied by auxtrace */
+			break;
 		default:
 			break;
 		}
@@ -905,6 +908,19 @@ static bool is_dummy_event(struct evsel *evsel)
 	       (evsel->core.attr.config == PERF_COUNT_SW_DUMMY);
 }
 
+struct perf_evsel_config_term *__perf_evsel__get_config_term(struct evsel *evsel,
+							     enum evsel_term_type type)
+{
+	struct perf_evsel_config_term *term, *found_term = NULL;
+
+	list_for_each_entry(term, &evsel->config_terms, list) {
+		if (term->type == type)
+			found_term = term;
+	}
+
+	return found_term;
+}
+
 /*
  * The enable_on_exec/disabled value strategy:
  *

tools/perf/util/evsel_config.h

@@ -25,6 +25,7 @@ enum evsel_term_type {
 	PERF_EVSEL__CONFIG_TERM_BRANCH,
 	PERF_EVSEL__CONFIG_TERM_PERCORE,
 	PERF_EVSEL__CONFIG_TERM_AUX_OUTPUT,
+	PERF_EVSEL__CONFIG_TERM_AUX_SAMPLE_SIZE,
 };
 
 struct perf_evsel_config_term {
@@ -44,7 +45,17 @@ struct perf_evsel_config_term {
 		unsigned long max_events;
 		bool	      percore;
 		bool	      aux_output;
+		u32	      aux_sample_size;
 	} val;
 	bool weak;
 };
+
+struct evsel;
+
+struct perf_evsel_config_term *__perf_evsel__get_config_term(struct evsel *evsel,
+							     enum evsel_term_type type);
+
+#define perf_evsel__get_config_term(evsel, type) \
+	__perf_evsel__get_config_term(evsel, PERF_EVSEL__CONFIG_TERM_ ## type)
+
 #endif // __PERF_EVSEL_CONFIG_H

tools/perf/util/parse-events.c

@@ -996,6 +996,7 @@ static const char *config_term_names[__PARSE_EVENTS__TERM_TYPE_NR] = {
 	[PARSE_EVENTS__TERM_TYPE_DRV_CFG]		= "driver-config",
 	[PARSE_EVENTS__TERM_TYPE_PERCORE]		= "percore",
 	[PARSE_EVENTS__TERM_TYPE_AUX_OUTPUT]		= "aux-output",
+	[PARSE_EVENTS__TERM_TYPE_AUX_SAMPLE_SIZE]	= "aux-sample-size",
 };
 
 static bool config_term_shrinked;
@@ -1126,6 +1127,15 @@ do {									   \
 	case PARSE_EVENTS__TERM_TYPE_AUX_OUTPUT:
 		CHECK_TYPE_VAL(NUM);
 		break;
+	case PARSE_EVENTS__TERM_TYPE_AUX_SAMPLE_SIZE:
+		CHECK_TYPE_VAL(NUM);
+		if (term->val.num > UINT_MAX) {
+			parse_events__handle_error(err, term->err_val,
+						strdup("too big"),
+						NULL);
+			return -EINVAL;
+		}
+		break;
 	default:
 		parse_events__handle_error(err, term->err_term,
 				strdup("unknown term"),
@@ -1177,6 +1187,7 @@ static int config_term_tracepoint(struct perf_event_attr *attr,
 	case PARSE_EVENTS__TERM_TYPE_OVERWRITE:
 	case PARSE_EVENTS__TERM_TYPE_NOOVERWRITE:
 	case PARSE_EVENTS__TERM_TYPE_AUX_OUTPUT:
+	case PARSE_EVENTS__TERM_TYPE_AUX_SAMPLE_SIZE:
 		return config_term_common(attr, term, err);
 	default:
 		if (err) {
@@ -1272,6 +1283,9 @@ do {								\
 		case PARSE_EVENTS__TERM_TYPE_AUX_OUTPUT:
 			ADD_CONFIG_TERM(AUX_OUTPUT, aux_output, term->val.num ? 1 : 0);
 			break;
+		case PARSE_EVENTS__TERM_TYPE_AUX_SAMPLE_SIZE:
+			ADD_CONFIG_TERM(AUX_SAMPLE_SIZE, aux_sample_size, term->val.num);
+			break;
 		default:
 			break;
 		}

tools/perf/util/parse-events.h

@@ -77,6 +77,7 @@ enum {
 	PARSE_EVENTS__TERM_TYPE_DRV_CFG,
 	PARSE_EVENTS__TERM_TYPE_PERCORE,
 	PARSE_EVENTS__TERM_TYPE_AUX_OUTPUT,
+	PARSE_EVENTS__TERM_TYPE_AUX_SAMPLE_SIZE,
 	__PARSE_EVENTS__TERM_TYPE_NR,
 };
 

tools/perf/util/parse-events.l

@@ -285,6 +285,7 @@ overwrite		{ return term(yyscanner, PARSE_EVENTS__TERM_TYPE_OVERWRITE); }
 no-overwrite		{ return term(yyscanner, PARSE_EVENTS__TERM_TYPE_NOOVERWRITE); }
 percore			{ return term(yyscanner, PARSE_EVENTS__TERM_TYPE_PERCORE); }
 aux-output		{ return term(yyscanner, PARSE_EVENTS__TERM_TYPE_AUX_OUTPUT); }
+aux-sample-size		{ return term(yyscanner, PARSE_EVENTS__TERM_TYPE_AUX_SAMPLE_SIZE); }
 ,			{ return ','; }
 "/"			{ BEGIN(INITIAL); return '/'; }
 {name_minus}		{ return str(yyscanner, PE_NAME); }