From 4a159e6049f319bef6f9e6d2ccdd322f57d24830 Mon Sep 17 00:00:00 2001 From: Xu Yang Date: Thu, 7 Nov 2024 08:20:28 -0800 Subject: perf jevents: fix breakage when do perf stat on system metric MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When do perf stat on sys metric, perf tool output nothing now: $ perf stat -a -M imx95_ddr_read.all -I 1000 $ This command runs on an arm64 machine and the Soc has one DDR hw pmu except one armv8_cortex_a55 pmu. Their maps show as follows: const struct pmu_events_map pmu_events_map[] = { { .arch = "arm64", .cpuid = "0x00000000410fd050", .event_table = { .pmus = pmu_events__arm_cortex_a55, .num_pmus = ARRAY_SIZE(pmu_events__arm_cortex_a55) }, .metric_table = { .pmus = NULL, .num_pmus = 0 } }, static const struct pmu_sys_events pmu_sys_event_tables[] = { { .event_table = { .pmus = pmu_events__freescale_imx95_sys, .num_pmus = ARRAY_SIZE(pmu_events__freescale_imx95_sys) }, .metric_table = { .pmus = pmu_metrics__freescale_imx95_sys, .num_pmus = ARRAY_SIZE(pmu_metrics__freescale_imx95_sys) }, .name = "pmu_events__freescale_imx95_sys", }, Currently, pmu_metrics_table__find() will return NULL when only do perf stat on sys metric. Then parse_groups() will never be called to parse sys metric_name, finally perf tool will exit directly. This should be a common problem. To fix the issue, this will keep the logic before commit f20c15d13f01 ("perf pmu-events: Remember the perf_events_map for a PMU") to return a empty metric table rather than a NULL pointer. This should be fine since the removed part just check if the table match provided metric_name. Without these code, the code in parse_groups() will also check the validity of metrci_name too. Fixes: f20c15d13f017d4b ("perf pmu-events: Remember the perf_events_map for a PMU") Reviewed-by: James Clark Signed-off-by: Xu Yang Tested-by: Xu Yang Acked-by: Ian Rogers Cc: Adrian Hunter Cc: Albert Ou Cc: Alexander Shishkin Cc: Alexandre Ghiti Cc: Athira Rajeev Cc: Benjamin Gray Cc: Ben Zong-You Xie Cc: Bibo Mao Cc: Clément Le Goffic Cc: Dima Kogan Cc: Dr. David Alan Gilbert Cc: Huacai Chen Cc: Ingo Molnar Cc: Jiri Olsa Cc: John Garry Cc: Kan Liang Cc: Leo Yan Cc: Mark Rutland Cc: Masami Hiramatsu Cc: Mike Leach Cc: Namhyung Kim Cc: Palmer Dabbelt Cc: Paul Walmsley Cc: Peter Zijlstra Cc: Ravi Bangoria Cc: Sandipan Das Cc: Will Deacon Cc: Yicong Yang Cc: linux-arm-kernel@lists.infradead.org Cc: linux-riscv@lists.infradead.org Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20241107162035.52206-2-irogers@google.com Signed-off-by: Ian Rogers Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/pmu-events/empty-pmu-events.c | 12 +----------- tools/perf/pmu-events/jevents.py | 12 +----------- 2 files changed, 2 insertions(+), 22 deletions(-) (limited to 'tools/perf') diff --git a/tools/perf/pmu-events/empty-pmu-events.c b/tools/perf/pmu-events/empty-pmu-events.c index 2b7516946ded..b8719dab264d 100644 --- a/tools/perf/pmu-events/empty-pmu-events.c +++ b/tools/perf/pmu-events/empty-pmu-events.c @@ -585,17 +585,7 @@ const struct pmu_metrics_table *perf_pmu__find_metrics_table(struct perf_pmu *pm if (!map) return NULL; - if (!pmu) - return &map->metric_table; - - for (size_t i = 0; i < map->metric_table.num_pmus; i++) { - const struct pmu_table_entry *table_pmu = &map->metric_table.pmus[i]; - const char *pmu_name = &big_c_string[table_pmu->pmu_name.offset]; - - if (pmu__name_match(pmu, pmu_name)) - return &map->metric_table; - } - return NULL; + return &map->metric_table; } const struct pmu_events_table *find_core_events_table(const char *arch, const char *cpuid) diff --git a/tools/perf/pmu-events/jevents.py b/tools/perf/pmu-events/jevents.py index 6e71b09dbc2a..70f4fd5395fb 100755 --- a/tools/perf/pmu-events/jevents.py +++ b/tools/perf/pmu-events/jevents.py @@ -1101,17 +1101,7 @@ const struct pmu_metrics_table *perf_pmu__find_metrics_table(struct perf_pmu *pm if (!map) return NULL; - if (!pmu) - return &map->metric_table; - - for (size_t i = 0; i < map->metric_table.num_pmus; i++) { - const struct pmu_table_entry *table_pmu = &map->metric_table.pmus[i]; - const char *pmu_name = &big_c_string[table_pmu->pmu_name.offset]; - - if (pmu__name_match(pmu, pmu_name)) - return &map->metric_table; - } - return NULL; + return &map->metric_table; } const struct pmu_events_table *find_core_events_table(const char *arch, const char *cpuid) -- cgit v1.2.3