Commit e6ff1eed authored by Ian Rogers's avatar Ian Rogers Committed by Arnaldo Carvalho de Melo
Browse files

perf pmu: Lazily add JSON events 



Rather than scanning all JSON events and adding them when a PMU is
created, add the alias when the JSON event is needed.

Average core PMU scanning run time reduced by 60.2%. Average PMU
scanning run time reduced by 15%. Page faults with no events reduced by
74 page faults, 4% of total.

Signed-off-by: default avatarIan Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Gaosheng Cui <cuigaosheng1@huawei.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jing Zhang <renyu.zj@linux.alibaba.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20230824041330.266337-14-irogers@google.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 7c52f10c

tools/perf/pmu-events/empty-pmu-events.c

+14 −0
Original line number Diff line number Diff line
@@ -298,6 +298,20 @@ int pmu_events_table__find_event(const struct pmu_events_table *table, 
        return -1000;

}



size_t pmu_events_table__num_events(const struct pmu_events_table *table,

                                    struct perf_pmu *pmu)

{

        size_t count = 0;



	for (const struct pmu_event *pe = &table->entries[0]; pe->name; pe++) {

                if (pmu && !pmu__name_match(pmu, pe->pmu))

                        continue;



		count++;

	}

        return count;

}



int pmu_metrics_table__for_each_metric(const struct pmu_metrics_table *table, pmu_metric_iter_fn fn,

				      void *data)

{

tools/perf/pmu-events/jevents.py

+15 −0
Original line number Diff line number Diff line
@@ -909,6 +909,21 @@ int pmu_events_table__find_event(const struct pmu_events_table *table, 
        return -1000;

}



size_t pmu_events_table__num_events(const struct pmu_events_table *table,

                                    struct perf_pmu *pmu)

{

        size_t count = 0;



        for (size_t i = 0; i < table->num_pmus; i++) {

                const struct pmu_table_entry *table_pmu = &table->pmus[i];

                const char *pmu_name = &big_c_string[table_pmu->pmu_name.offset];



                if (pmu__name_match(pmu, pmu_name))

                        count += table_pmu->num_entries;

        }

        return count;

}



static int pmu_metrics_table__for_each_metric_pmu(const struct pmu_metrics_table *table,

                                                const struct pmu_table_entry *pmu,

                                                pmu_metric_iter_fn fn,

tools/perf/pmu-events/pmu-events.h

+4 −0
Original line number Diff line number Diff line
@@ -3,6 +3,7 @@ 
#define PMU_EVENTS_H



#include <stdbool.h>

#include <stddef.h>



struct perf_pmu;
@@ -86,6 +87,9 @@ int pmu_events_table__find_event(const struct pmu_events_table *table, 
                                 const char *name,

                                 pmu_event_iter_fn fn,

				 void *data);

size_t pmu_events_table__num_events(const struct pmu_events_table *table,

				    struct perf_pmu *pmu);



int pmu_metrics_table__for_each_metric(const struct pmu_metrics_table *table, pmu_metric_iter_fn fn,

				     void *data);

tools/perf/tests/pmu-events.c

+2 −0
Original line number Diff line number Diff line
@@ -546,6 +546,7 @@ static int __test_core_pmu_event_aliases(char *pmu_name, int *count) 


	pmu->events_table = table;

	pmu_add_cpu_aliases_table(pmu, table);

	pmu->cpu_aliases_added = true;



	res = pmu_events_table__find_event(table, pmu, "bp_l1_btb_correct", NULL, NULL);

	if (res != 0) {
@@ -586,6 +587,7 @@ static int __test_uncore_pmu_event_aliases(struct perf_pmu_test_pmu *test_pmu) 
		return -1;

	pmu->events_table = events_table;

	pmu_add_cpu_aliases_table(pmu, events_table);

	pmu->cpu_aliases_added = true;

	pmu_add_sys_aliases(pmu);



	/* Count how many aliases we generated */

tools/perf/util/pmu.c

+38 −12
Original line number Diff line number Diff line
@@ -523,8 +523,9 @@ static int perf_pmu__new_alias(struct perf_pmu *pmu, int dirfd, const char *name 
	if (!pe) {

		/* Update an event from sysfs with json data. */

		if (pmu->events_table) {

			pmu_events_table__find_event(pmu->events_table, pmu, name,

						     update_alias, alias);

			if (pmu_events_table__find_event(pmu->events_table, pmu, name,

							 update_alias, alias) == 0)

				pmu->loaded_json_aliases++;

		}

	}
@@ -548,6 +549,10 @@ static int perf_pmu__new_alias(struct perf_pmu *pmu, int dirfd, const char *name 
					 "%s=%s", term->config, term->val.str);

	}

	alias->str = strdup(newval);

	if (!pe)

		pmu->sysfs_aliases++;

	else

		pmu->loaded_json_aliases++;

	list_add_tail(&alias->list, &pmu->aliases);

	return 0;

}
@@ -878,7 +883,11 @@ static void pmu_add_cpu_aliases(struct perf_pmu *pmu) 
	if (!pmu->events_table)

		return;



	if (pmu->cpu_aliases_added)

		return;



	pmu_add_cpu_aliases_table(pmu, pmu->events_table);

	pmu->cpu_aliases_added = true;

}



static int pmu_add_sys_aliases_iter_fn(const struct pmu_event *pe,
@@ -990,7 +999,6 @@ struct perf_pmu *perf_pmu__lookup(struct list_head *pmus, int dirfd, const char 
		pmu->id = pmu_id(name);

	pmu->max_precise = pmu_max_precise(dirfd, pmu);

	pmu->events_table = perf_pmu__find_events_table(pmu);

	pmu_add_cpu_aliases(pmu);

	pmu_add_sys_aliases(pmu);

	list_add_tail(&pmu->list, pmus);
@@ -1368,6 +1376,7 @@ int perf_pmu__config(struct perf_pmu *pmu, struct perf_event_attr *attr, 
static struct perf_pmu_alias *pmu_find_alias(struct perf_pmu *pmu,

					     struct parse_events_term *term)

{

	struct perf_pmu_alias *alias;

	char *name;



	if (parse_events__is_hardcoded_term(term))
@@ -1388,7 +1397,18 @@ static struct perf_pmu_alias *pmu_find_alias(struct perf_pmu *pmu, 
		return NULL;

	}



	return perf_pmu__find_alias(pmu, name);

	alias = perf_pmu__find_alias(pmu, name);

	if (alias || pmu->cpu_aliases_added)

		return alias;



	/* Alias doesn't exist, try to get it from the json events. */

	if (pmu->events_table &&

	    pmu_events_table__find_event(pmu->events_table, pmu, name,

				         pmu_add_cpu_aliases_map_callback,

				         pmu) == 0) {

		alias = perf_pmu__find_alias(pmu, name);

	}

	return alias;

}
@@ -1555,18 +1575,23 @@ bool perf_pmu__auto_merge_stats(const struct perf_pmu *pmu) 
	return !pmu->is_core || perf_pmus__num_core_pmus() == 1;

}



bool perf_pmu__have_event(const struct perf_pmu *pmu, const char *name)

bool perf_pmu__have_event(struct perf_pmu *pmu, const char *name)

{

	return perf_pmu__find_alias(pmu, name) != NULL;

	if (perf_pmu__find_alias(pmu, name) != NULL)

		return true;

	if (pmu->cpu_aliases_added || !pmu->events_table)

		return false;

	return pmu_events_table__find_event(pmu->events_table, pmu, name, NULL, NULL) == 0;

}



size_t perf_pmu__num_events(const struct perf_pmu *pmu)

size_t perf_pmu__num_events(struct perf_pmu *pmu)

{

	struct list_head *list;

	size_t nr = 0;

	size_t nr = pmu->sysfs_aliases;



	list_for_each(list, &pmu->aliases)

		nr++;

	if (pmu->cpu_aliases_added)

		 nr += pmu->loaded_json_aliases;

	else if (pmu->events_table)

		nr += pmu_events_table__num_events(pmu->events_table, pmu) - pmu->loaded_json_aliases;



	return pmu->selectable ? nr + 1 : nr;

}
@@ -1604,7 +1629,7 @@ static char *format_alias(char *buf, int len, const struct perf_pmu *pmu, 
	return buf;

}



int perf_pmu__for_each_event(const struct perf_pmu *pmu, void *state, pmu_event_callback cb)

int perf_pmu__for_each_event(struct perf_pmu *pmu, void *state, pmu_event_callback cb)

{

	char buf[1024];

	struct perf_pmu_alias *event;
@@ -1613,6 +1638,7 @@ int perf_pmu__for_each_event(const struct perf_pmu *pmu, void *state, pmu_event_ 
	};

	int ret = 0;



	pmu_add_cpu_aliases(pmu);

	list_for_each_entry(event, &pmu->aliases, list) {

		size_t buf_used;