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

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

[Zide Chen]

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: 5b546de9cc17 ("perf topdown: Use attribute to see an event is a topdown metic or slots")
Signed-off-by: Zide Chen <zide.chen@intel.com>
---
 tools/perf/arch/x86/tests/topdown.c | 28 ++++++++++++++++++++++++++++
 tools/perf/arch/x86/util/topdown.c  |  3 +--
 2 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/tools/perf/arch/x86/tests/topdown.c b/tools/perf/arch/x86/tests/topdown.c
index 2b6f47ce4932..b1ce9f83db00 100644
--- a/tools/perf/arch/x86/tests/topdown.c
+++ b/tools/perf/arch/x86/tests/topdown.c
@@ -229,10 +229,38 @@ 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, }
 };
 
diff --git a/tools/perf/arch/x86/util/topdown.c b/tools/perf/arch/x86/util/topdown.c
index bafd285119d7..64bc64e335a2 100644
--- a/tools/perf/arch/x86/util/topdown.c
+++ b/tools/perf/arch/x86/util/topdown.c
@@ -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)
-- 
2.55.0

Re: [PATCH] perf topdown: Don't require config1==0 for a slots event

[Ian Rogers]

On Wed, Sep 16, 2026 at 1:37 PM Zide Chen <zide.chen@intel.com> wrote:
>
> 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: 5b546de9cc17 ("perf topdown: Use attribute to see an event is a topdown metic or slots")
> Signed-off-by: Zide Chen <zide.chen@intel.com>

Reviewed-by: Ian Rogers <irogers@google.com>

Note, there's a Sashiko warning about a potentially missing #include
for musl compatibility that maybe you or Arnaldo could address.

Thanks,
Ian

> ---
>  tools/perf/arch/x86/tests/topdown.c | 28 ++++++++++++++++++++++++++++
>  tools/perf/arch/x86/util/topdown.c  |  3 +--
>  2 files changed, 29 insertions(+), 2 deletions(-)
>
> diff --git a/tools/perf/arch/x86/tests/topdown.c b/tools/perf/arch/x86/tests/topdown.c
> index 2b6f47ce4932..b1ce9f83db00 100644
> --- a/tools/perf/arch/x86/tests/topdown.c
> +++ b/tools/perf/arch/x86/tests/topdown.c
> @@ -229,10 +229,38 @@ 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, }
>  };
>
> diff --git a/tools/perf/arch/x86/util/topdown.c b/tools/perf/arch/x86/util/topdown.c
> index bafd285119d7..64bc64e335a2 100644
> --- a/tools/perf/arch/x86/util/topdown.c
> +++ b/tools/perf/arch/x86/util/topdown.c
> @@ -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)
> --
> 2.55.0
>

Re: [PATCH] perf topdown: Don't require config1==0 for a slots event

[Mi, Dapeng]

LGTM. Thanks.

Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>

On 9/17/2026 4:27 AM, Zide Chen wrote:
> 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: 5b546de9cc17 ("perf topdown: Use attribute to see an event is a topdown metic or slots")
> Signed-off-by: Zide Chen <zide.chen@intel.com>
> ---
>  tools/perf/arch/x86/tests/topdown.c | 28 ++++++++++++++++++++++++++++
>  tools/perf/arch/x86/util/topdown.c  |  3 +--
>  2 files changed, 29 insertions(+), 2 deletions(-)
>
> diff --git a/tools/perf/arch/x86/tests/topdown.c b/tools/perf/arch/x86/tests/topdown.c
> index 2b6f47ce4932..b1ce9f83db00 100644
> --- a/tools/perf/arch/x86/tests/topdown.c
> +++ b/tools/perf/arch/x86/tests/topdown.c
> @@ -229,10 +229,38 @@ 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, }
>  };
>  
> diff --git a/tools/perf/arch/x86/util/topdown.c b/tools/perf/arch/x86/util/topdown.c
> index bafd285119d7..64bc64e335a2 100644
> --- a/tools/perf/arch/x86/util/topdown.c
> +++ b/tools/perf/arch/x86/util/topdown.c
> @@ -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)

Re: [PATCH] perf topdown: Don't require config1==0 for a slots event

[Arnaldo Carvalho de Melo]

On Wed, Sep 16, 2026 at 02:22:45PM -0700, Ian Rogers wrote:
> On Wed, Sep 16, 2026 at 1:37 PM Zide Chen <zide.chen@intel.com> wrote:
> >
> > 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: 5b546de9cc17 ("perf topdown: Use attribute to see an event is a topdown metic or slots")
> > Signed-off-by: Zide Chen <zide.chen@intel.com>
> 
> Reviewed-by: Ian Rogers <irogers@google.com>
> 
> Note, there's a Sashiko warning about a potentially missing #include
> for musl compatibility that maybe you or Arnaldo could address.

Merging, will look add address that comment,

Thanks,

- Arnaldo
 
> Thanks,
> Ian
> 
> > ---
> >  tools/perf/arch/x86/tests/topdown.c | 28 ++++++++++++++++++++++++++++
> >  tools/perf/arch/x86/util/topdown.c  |  3 +--
> >  2 files changed, 29 insertions(+), 2 deletions(-)
> >
> > diff --git a/tools/perf/arch/x86/tests/topdown.c b/tools/perf/arch/x86/tests/topdown.c
> > index 2b6f47ce4932..b1ce9f83db00 100644
> > --- a/tools/perf/arch/x86/tests/topdown.c
> > +++ b/tools/perf/arch/x86/tests/topdown.c
> > @@ -229,10 +229,38 @@ 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, }
> >  };
> >
> > diff --git a/tools/perf/arch/x86/util/topdown.c b/tools/perf/arch/x86/util/topdown.c
> > index bafd285119d7..64bc64e335a2 100644
> > --- a/tools/perf/arch/x86/util/topdown.c
> > +++ b/tools/perf/arch/x86/util/topdown.c
> > @@ -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)
> > --
> > 2.55.0
> >

Re: [PATCH] perf topdown: Don't require config1==0 for a slots event

[Mi, Dapeng]

On 9/19/2026 4:13 AM, Arnaldo Carvalho de Melo wrote:
> On Wed, Sep 16, 2026 at 02:22:45PM -0700, Ian Rogers wrote:
>> On Wed, Sep 16, 2026 at 1:37 PM Zide Chen <zide.chen@intel.com> wrote:
>>> 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: 5b546de9cc17 ("perf topdown: Use attribute to see an event is a topdown metic or slots")
>>> Signed-off-by: Zide Chen <zide.chen@intel.com>
>> Reviewed-by: Ian Rogers <irogers@google.com>
>>
>> Note, there's a Sashiko warning about a potentially missing #include
>> for musl compatibility that maybe you or Arnaldo could address.
> Merging, will look add address that comment,

@Arnaldo, Zide posted the v2 patch to address the Sashiko comments.
https://lore.kernel.org/all/20260917181016.381994-1-zide.chen@intel.com/

You may directly merge that patch. :) 

Thanks.


>
> Thanks,
>
> - Arnaldo
>  
>> Thanks,
>> Ian
>>
>>> ---
>>>  tools/perf/arch/x86/tests/topdown.c | 28 ++++++++++++++++++++++++++++
>>>  tools/perf/arch/x86/util/topdown.c  |  3 +--
>>>  2 files changed, 29 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/tools/perf/arch/x86/tests/topdown.c b/tools/perf/arch/x86/tests/topdown.c
>>> index 2b6f47ce4932..b1ce9f83db00 100644
>>> --- a/tools/perf/arch/x86/tests/topdown.c
>>> +++ b/tools/perf/arch/x86/tests/topdown.c
>>> @@ -229,10 +229,38 @@ 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, }
>>>  };
>>>
>>> diff --git a/tools/perf/arch/x86/util/topdown.c b/tools/perf/arch/x86/util/topdown.c
>>> index bafd285119d7..64bc64e335a2 100644
>>> --- a/tools/perf/arch/x86/util/topdown.c
>>> +++ b/tools/perf/arch/x86/util/topdown.c
>>> @@ -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)
>>> --
>>> 2.55.0
>>>

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

[Zide Chen]

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: 5b546de9cc17 ("perf topdown: Use attribute to see an event is a topdown metic or slots")
Signed-off-by: Zide Chen <zide.chen@intel.com>
Reviewed-by: Ian Rogers <irogers@google.com>
Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
---
v2: include stdio.h and string.h for musl compatibility.
---
 tools/perf/arch/x86/tests/topdown.c | 30 +++++++++++++++++++++++++++++
 tools/perf/arch/x86/util/topdown.c  |  3 +--
 2 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/tools/perf/arch/x86/tests/topdown.c b/tools/perf/arch/x86/tests/topdown.c
index 2b6f47ce4932..520075329c37 100644
--- a/tools/perf/arch/x86/tests/topdown.c
+++ b/tools/perf/arch/x86/tests/topdown.c
@@ -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, }
 };
 
diff --git a/tools/perf/arch/x86/util/topdown.c b/tools/perf/arch/x86/util/topdown.c
index bafd285119d7..64bc64e335a2 100644
--- a/tools/perf/arch/x86/util/topdown.c
+++ b/tools/perf/arch/x86/util/topdown.c
@@ -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)
-- 
2.55.0