linux-kernel - [PATCH v1 6/7] perf pmu-events: Remember the events and metrics table

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Message-Id: <20231007021326.4156714-7-irogers@google.com>
Date:   Fri,  6 Oct 2023 19:13:25 -0700
From:   Ian Rogers <irogers@...gle.com>
To:     Suzuki K Poulose <suzuki.poulose@....com>,
        Mike Leach <mike.leach@...aro.org>,
        James Clark <james.clark@....com>,
        Leo Yan <leo.yan@...aro.org>,
        John Garry <john.g.garry@...cle.com>,
        Will Deacon <will@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Ian Rogers <irogers@...gle.com>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Thomas Richter <tmricht@...ux.ibm.com>,
        Ravi Bangoria <ravi.bangoria@....com>,
        Kajol Jain <kjain@...ux.ibm.com>,
        Jing Zhang <renyu.zj@...ux.alibaba.com>,
        Kan Liang <kan.liang@...ux.intel.com>,
        Yang Jihong <yangjihong1@...wei.com>,
        coresight@...ts.linaro.org, linux-arm-kernel@...ts.infradead.org,
        linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v1 6/7] perf pmu-events: Remember the events and metrics table

strcmp_cpuid_str performs regular expression comparisons. Avoid
repeated computation of the table by remembering the table in a
static.

Signed-off-by: Ian Rogers <irogers@...gle.com>
---
 tools/perf/pmu-events/jevents.py | 48 +++++++++++++++++++-------------
 1 file changed, 28 insertions(+), 20 deletions(-)

diff --git a/tools/perf/pmu-events/jevents.py b/tools/perf/pmu-events/jevents.py
index fd009752b427..8d8d5088c53c 100755
--- a/tools/perf/pmu-events/jevents.py
+++ b/tools/perf/pmu-events/jevents.py
@@ -978,28 +978,32 @@ int pmu_metrics_table__for_each_metric(const struct pmu_metrics_table *table,
 
 const struct pmu_events_table *perf_pmu__find_events_table(struct perf_pmu *pmu)
 {
-        const struct pmu_events_table *table = NULL;
-        char *cpuid = perf_pmu__getcpuid(pmu);
+        static const struct pmu_events_table *table;
         size_t i;
 
-        /* on some platforms which uses cpus map, cpuid can be NULL for
-         * PMUs other than CORE PMUs.
-         */
-        if (!cpuid)
-                return NULL;
-
-        i = 0;
-        for (;;) {
-                const struct pmu_events_map *map = &pmu_events_map[i++];
-                if (!map->arch)
-                        break;
-
-                if (!strcmp_cpuid_str(map->cpuid, cpuid)) {
-                        table = &map->event_table;
-                        break;
+        if (!table) {
+                char *cpuid = perf_pmu__getcpuid(pmu);
+
+                /*
+                 * On some platforms which uses cpus map, cpuid can be NULL for
+                 * PMUs other than CORE PMUs.
+                 */
+                if (!cpuid)
+                        return NULL;
+
+                i = 0;
+                for (;;) {
+                        const struct pmu_events_map *map = &pmu_events_map[i++];
+                        if (!map->arch)
+                                break;
+
+                        if (!strcmp_cpuid_str(map->cpuid, cpuid)) {
+                                table = &map->event_table;
+                                break;
+                        }
                 }
+                free(cpuid);
         }
-        free(cpuid);
         if (!pmu)
                 return table;
 
@@ -1015,13 +1019,17 @@ const struct pmu_events_table *perf_pmu__find_events_table(struct perf_pmu *pmu)
 
 const struct pmu_metrics_table *perf_pmu__find_metrics_table(struct perf_pmu *pmu)
 {
-        const struct pmu_metrics_table *table = NULL;
-        char *cpuid = perf_pmu__getcpuid(pmu);
+        static const struct pmu_metrics_table *table;
+        char *cpuid;
         int i;
 
+        if (table)
+                return table;
+
         /* on some platforms which uses cpus map, cpuid can be NULL for
          * PMUs other than CORE PMUs.
          */
+        cpuid = perf_pmu__getcpuid(pmu);
         if (!cpuid)
                 return NULL;
 
-- 
2.42.0.609.gbb76f46606-goog