github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-11-07 06:17:02 +01:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

perf topdown: Don't require config1==0 for a slots event

Browse Source 
arch_is_topdown_slots() requires config1 == 0, so it misidentified
"cpu/slots,metrics_clear=1/" as not being the slots event, and an
additional slots event gets inserted, which fails event scheduling
since the group now needs two fixed counter 3.

  $ perf stat -e "{cpu/slots,metrics_clear=1/,cpu/topdown-retiring/}" -- sleep 1
  WARNING: events were regrouped to match PMUs
       <not counted>      slots
     <not supported>      cpu/slots,metrics_clear=1/
       <not counted>      cpu/topdown-retiring/

Drop the config1 == 0 check from arch_is_topdown_slots(). This is
safe: config1 has no bearing on the event's identifying config value
(TOPDOWN_SLOTS, 0x0400).

The attr.type == PERF_TYPE_RAW check is what actually matters: only the
core PMU is registered with PERF_TYPE_RAW, and on x86, 0x400 is
guaranteed to be slots event on core CPU.

arch_is_topdown_metrics() keeps its own config1 == 0 check, since
genuine metrics events have no "metrics_clear" and config1 remains 0.

Add a test verifying that an explicit "slots,metrics_clear=1" event in
a group does not trigger an extra slots event injection.

Fixes: 5b546de9cc ("perf topdown: Use attribute to see an event is a topdown metic or slots")
Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Reviewed-by: Ian Rogers <irogers@google.com>
Signed-off-by: Zide Chen <zide.chen@intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
[ Add missing stdio.h and string.h as noticed by Sashiko ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Zide Chen 2026-09-16 13:27:40 -07:00 committed by Arnaldo Carvalho de Melo
parent 86a2781167
commit 0824af00a8
2 changed files with 31 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

30
tools/perf/arch/x86/tests/topdown.c
View File

@ -1,5 +1,7 @@
// SPDX-License-Identifier: GPL-2.0
#include <errno.h>
#include <stdio.h>
#include <string.h>
#include "arch-tests.h"
#include "../util/topdown.h"
#include "debug.h"
@ -229,10 +231,38 @@ static int test__x86_topdown_slots_injection(struct test_suite *test __maybe_unu
return TEST_OK;
}
/*
* An explicit "slots,metrics_clear=1" event is still the slots event and
* must not cause an extra slots event to be injected into the group.
*/
static int test__x86_topdown_metrics_clear(struct test_suite *test __maybe_unused,
int subtest __maybe_unused)
{
struct perf_pmu *pmu;
char event_str[128];
int ret;
if (!topdown_sys_has_perf_metrics())
return TEST_OK;
pmu = perf_pmus__find_by_type(PERF_TYPE_RAW);
if (!pmu || !perf_pmu__has_format(pmu, "metrics_clear"))
return TEST_OK;
snprintf(event_str, sizeof(event_str),
"{%s/slots,metrics_clear=1/,%s/topdown-retiring/}",
pmu->name, pmu->name);
ret = test_sort(event_str, 2, 1);
TEST_ASSERT_EQUAL("explicit metrics_clear slots event isn't duplicated", ret, TEST_OK);
return TEST_OK;
}
static struct test_case x86_topdown_tests[] = {
TEST_CASE("topdown events", x86_topdown),
TEST_CASE("topdown sorting", x86_topdown_sorting),
TEST_CASE("topdown slots injection", x86_topdown_slots_injection),
TEST_CASE("topdown metrics_clear no extra slots", x86_topdown_metrics_clear),
{ .name = NULL, }
};

3
tools/perf/arch/x86/util/topdown.c
View File

@ -37,8 +37,7 @@ bool topdown_sys_has_perf_metrics(void)
bool arch_is_topdown_slots(const struct evsel *evsel)
{
return evsel->core.attr.type == PERF_TYPE_RAW &&
evsel->core.attr.config == TOPDOWN_SLOTS &&
evsel->core.attr.config1 == 0;
evsel->core.attr.config == TOPDOWN_SLOTS;
}
bool arch_is_topdown_metrics(const struct evsel *evsel)