From: Xu Yang <xu.yang_2@xxxxxxx>
commit 4a159e6049f319bef6f9e6d2ccdd322f57d24830 upstream.
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 <james.clark@xxxxxxxxxx>
Signed-off-by: Xu Yang <xu.yang_2@xxxxxxx>
Tested-by: Xu Yang <xu.yang_2@xxxxxxx>
Acked-by: Ian Rogers <irogers@xxxxxxxxxx>
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Albert Ou <aou@xxxxxxxxxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Alexandre Ghiti <alexghiti@xxxxxxxxxxxx>
Cc: Athira Rajeev <atrajeev@xxxxxxxxxxxxxxxxxx>
Cc: Benjamin Gray <bgray@xxxxxxxxxxxxx>
Cc: Ben Zong-You Xie <ben717@xxxxxxxxxxxxx>
Cc: Bibo Mao <maobibo@xxxxxxxxxxx>
Cc: Clément Le Goffic <clement.legoffic@xxxxxxxxxxx>
Cc: Dima Kogan <dima@xxxxxxxxxxxxxxx>
Cc: Dr. David Alan Gilbert <linux@xxxxxxxxxxx>
Cc: Huacai Chen <chenhuacai@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: John Garry <john.g.garry@xxxxxxxxxx>
Cc: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
Cc: Leo Yan <leo.yan@xxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: Mike Leach <mike.leach@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Palmer Dabbelt <palmer@xxxxxxxxxxx>
Cc: Paul Walmsley <paul.walmsley@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Ravi Bangoria <ravi.bangoria@xxxxxxx>
Cc: Sandipan Das <sandipan.das@xxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Cc: Yicong Yang <yangyicong@xxxxxxxxxxxxx>
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Cc: linux-riscv@xxxxxxxxxxxxxxxxxxx
Cc: stable@xxxxxxxxxxxxxxx
Link: https://lore.kernel.org/r/20241107162035.52206-2-irogers@xxxxxxxxxx
Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
tools/perf/pmu-events/empty-pmu-events.c | 12 +-----------
tools/perf/pmu-events/jevents.py | 12 +-----------
2 files changed, 2 insertions(+), 22 deletions(-)
--- a/tools/perf/pmu-events/empty-pmu-events.c
+++ b/tools/perf/pmu-events/empty-pmu-events.c
@@ -539,17 +539,7 @@ const struct pmu_metrics_table *perf_pmu
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)
--- a/tools/perf/pmu-events/jevents.py
+++ b/tools/perf/pmu-events/jevents.py
@@ -1089,17 +1089,7 @@ const struct pmu_metrics_table *perf_pmu
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)
Patches currently in stable-queue which might be from xu.yang_2@xxxxxxx are
queue-6.12/perf-jevents-fix-breakage-when-do-perf-stat-on-system-metric.patch
