perf pmu: Cache JSON events table

Cache the JSON events table so that finding it isn't done per
event/alias.

Change the events table find so that when the PMU is given, if the PMU
has no JSON events return null.

Update usage to always use the PMU variable.

Signed-off-by: Ian 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/20230824041330.266337-13-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/pmu-events/jevents.py

@@ -948,7 +948,7 @@ def print_system_mapping_table() -> None:
 {
         const struct pmu_events_table *table = NULL;
         char *cpuid = perf_pmu__getcpuid(pmu);
-        int i;
+        size_t i;
 
         /* on some platforms which uses cpus map, cpuid can be NULL for
          * PMUs other than CORE PMUs.
@@ -968,7 +968,17 @@ def print_system_mapping_table() -> None:
                 }
         }
         free(cpuid);
-        return table;
+        if (!pmu)
+                return table;
+
+        for (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))
+                        return table;
+        }
+        return NULL;
 }
 
 const struct pmu_metrics_table *perf_pmu__find_metrics_table(struct perf_pmu *pmu)

tools/perf/tests/pmu-events.c

@@ -544,6 +544,7 @@ static int __test_core_pmu_event_aliases(char *pmu_name, int *count)
 	INIT_LIST_HEAD(&pmu->list);
 	pmu->name = strdup(pmu_name);
 
+	pmu->events_table = table;
 	pmu_add_cpu_aliases_table(pmu, table);
 
 	res = pmu_events_table__find_event(table, pmu, "bp_l1_btb_correct", NULL, NULL);
@@ -583,6 +584,7 @@ static int __test_uncore_pmu_event_aliases(struct perf_pmu_test_pmu *test_pmu)
 	events_table = find_core_events_table("testarch", "testcpu");
 	if (!events_table)
 		return -1;
+	pmu->events_table = events_table;
 	pmu_add_cpu_aliases_table(pmu, events_table);
 	pmu_add_sys_aliases(pmu);
 

tools/perf/util/pmu.c

@@ -522,10 +522,10 @@ 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. */
-		const struct pmu_events_table *table = perf_pmu__find_events_table(pmu);
-
-		if (table)
-			pmu_events_table__find_event(table, pmu, name, update_alias, alias);
+		if (pmu->events_table) {
+			pmu_events_table__find_event(pmu->events_table, pmu, name,
+						     update_alias, alias);
+		}
 	}
 
 	/* Scan event and remove leading zeroes, spaces, newlines, some
@@ -875,13 +875,10 @@ void pmu_add_cpu_aliases_table(struct perf_pmu *pmu, const struct pmu_events_tab
 
 static void pmu_add_cpu_aliases(struct perf_pmu *pmu)
 {
-	const struct pmu_events_table *table;
-
-	table = perf_pmu__find_events_table(pmu);
-	if (!table)
+	if (!pmu->events_table)
 		return;
 
-	pmu_add_cpu_aliases_table(pmu, table);
+	pmu_add_cpu_aliases_table(pmu, pmu->events_table);
 }
 
 static int pmu_add_sys_aliases_iter_fn(const struct pmu_event *pe,
@@ -992,6 +989,7 @@ struct perf_pmu *perf_pmu__lookup(struct list_head *pmus, int dirfd, const char
 	if (pmu->is_uncore)
 		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);

tools/perf/util/pmu.h

@@ -114,6 +114,10 @@ struct perf_pmu {
 	 * from json events in pmu-events.c.
 	 */
 	struct list_head aliases;
+	/**
+	 * @events_table: The events table for json events in pmu-events.c.
+	 */
+	const struct pmu_events_table *events_table;
 	/** @caps_initialized: Has the list caps been initialized? */
 	bool caps_initialized;
 	/** @nr_caps: The length of the list caps. */