[PATCH] perf tests: Add auto counter reload (ACR) sampling test

[PATCH] perf tests: Add auto counter reload (ACR) sampling test

[Dapeng Mi]

Add auto counter reload sampling test to verify that the intended event
records can be captured and the self-reloaded events won't generate any
records.

Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
---
 tools/perf/tests/shell/record.sh | 42 ++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/tools/perf/tests/shell/record.sh b/tools/perf/tests/shell/record.sh
index 7cb81cf3444a..1068843282f5 100755
--- a/tools/perf/tests/shell/record.sh
+++ b/tools/perf/tests/shell/record.sh
@@ -402,6 +402,47 @@ test_callgraph() {
   echo "Callgraph test [Success]"
 }
 
+test_acr_sampling() {
+  events="{instructions/period=20000,acr_mask=0x2/u,cycles/period=40000,acr_mask=0x3/u}"
+  pebs_events="{instructions/period=20000,acr_mask=0x2/pu,cycles/period=40000,acr_mask=0x3/u}"
+  echo "Auto counter reload sampling test"
+  if ! perf record -o "${perfdata}" -e "${events}" ${testprog} 2> /dev/null
+  then
+    echo "Auto counter reload sampling [Skipped not supported]"
+    return
+  fi
+  if ! perf script -i "${perfdata}" | grep -q "period=20000,acr_mask=0x2"
+  then
+    echo "Auto counter reload sampling [Failed missing instructions event]"
+    err=1
+    return
+  fi
+  if perf script -i "${perfdata}" | grep -q "period=40000,acr_mask=0x3"
+  then
+    echo "Auto counter reload sampling [Failed cycles event shouldn't be sampled]"
+    err=1
+    return
+  fi
+  if ! perf record -o "${perfdata}" -e "${pebs_events}" ${testprog} 2> /dev/null
+  then
+    echo "Auto counter reload PEBS sampling [Skipped not supported]"
+    return
+  fi
+  if ! perf script -i "${perfdata}" | grep -q "period=20000,acr_mask=0x2"
+  then
+    echo "Auto counter reload PEBS sampling [Failed missing instructions event]"
+    err=1
+    return
+  fi
+  if perf script -i "${perfdata}" | grep -q "period=40000,acr_mask=0x3"
+  then
+    echo "Auto counter reload PEBS sampling [Failed cycles event shouldn't be sampled]"
+    err=1
+    return
+  fi
+  echo "Auto counter reload sampling [Success]"
+}
+
 test_ratio_to_prev() {
   echo "ratio-to-prev test"
   if ! perf record -o /dev/null -e "{instructions, cycles/period=100000,ratio-to-prev=0.5/}" \
@@ -457,6 +498,7 @@ test_leader_sampling
 test_topdown_leader_sampling
 test_precise_max
 test_callgraph
+test_acr_sampling
 test_ratio_to_prev
 
 # restore the default value

base-commit: 4e03d6494f9504f8af46ba68a2a8b6877c196789
-- 
2.34.1

Re: [PATCH] perf tests: Add auto counter reload (ACR) sampling test

[sashiko-bot]

Sashiko AI review found 1 potential issue(s):
- [Medium] The test fails to genuinely verify that self-reloaded events do not generate records because the chosen sample periods and workload ensure the self-reloaded event never actually overflows.
--

commit 5e7a7e069f4c078327e3d8166d7f74d9084ec8a4
Author: Dapeng Mi <dapeng1.mi@linux.intel.com>

perf tests: Add auto counter reload (ACR) sampling test

This commit adds an auto counter reload sampling test to verify that the
intended event records can be captured and self-reloaded events do not
generate any records.

> diff --git a/tools/perf/tests/shell/record.sh b/tools/perf/tests/shell/record.sh
> index 7cb81cf3444a7..1068843282f51 100755
> --- a/tools/perf/tests/shell/record.sh
> +++ b/tools/perf/tests/shell/record.sh
[ ... ]
> @@ -402,6 +402,47 @@ test_callgraph() {
>    echo "Callgraph test [Success]"
>  }
>  
> +test_acr_sampling() {
> +  events="{instructions/period=20000,acr_mask=0x2/u,cycles/period=40000,acr_mask=0x3/u}"
> +  pebs_events="{instructions/period=20000,acr_mask=0x2/pu,cycles/period=40000,acr_mask=0x3/u}"

Does this test configuration actually verify that self-reloaded events do not
generate records?

The test runs the thloop workload, which is a tight CPU loop with an inherently
high IPC (typically > 0.5). With periods of 20000 for instructions and 40000
for cycles, the instructions event will always overflow first.

When the instructions event overflows, its acr_mask=0x2 triggers an auto-reload
of the cycles counter, resetting its progress toward overflow.

Because it is continually reset by the instructions event before reaching
40000, the cycles counter never overflows.

The test asserts that no records are generated for cycles and passes, but is
this simply because the event never fired rather than due to self-reloaded PMI
suppression working correctly?

If the hardware PMI suppression for self-reloaded events was broken, wouldn't
this test still pass?

Additionally, if the test ran on a system with IPC < 0.5, wouldn't the cycles
event overflow first, resetting both itself and instructions (acr_mask=0x3)?
This would prevent instructions from generating a record, causing the test
to fail.

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260413010920.546501-1-dapeng1.mi@linux.intel.com?part=1

Re: [PATCH] perf tests: Add auto counter reload (ACR) sampling test

[Ian Rogers]

On Sun, Apr 12, 2026 at 6:14 PM Dapeng Mi <dapeng1.mi@linux.intel.com> wrote:
>
> Add auto counter reload sampling test to verify that the intended event
> records can be captured and the self-reloaded events won't generate any
> records.
>
> Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
> ---
>  tools/perf/tests/shell/record.sh | 42 ++++++++++++++++++++++++++++++++
>  1 file changed, 42 insertions(+)
>
> diff --git a/tools/perf/tests/shell/record.sh b/tools/perf/tests/shell/record.sh
> index 7cb81cf3444a..1068843282f5 100755
> --- a/tools/perf/tests/shell/record.sh
> +++ b/tools/perf/tests/shell/record.sh
> @@ -402,6 +402,47 @@ test_callgraph() {
>    echo "Callgraph test [Success]"
>  }
>
> +test_acr_sampling() {
> +  events="{instructions/period=20000,acr_mask=0x2/u,cycles/period=40000,acr_mask=0x3/u}"
> +  pebs_events="{instructions/period=20000,acr_mask=0x2/pu,cycles/period=40000,acr_mask=0x3/u}"
> +  echo "Auto counter reload sampling test"
> +  if ! perf record -o "${perfdata}" -e "${events}" ${testprog} 2> /dev/null
> +  then
> +    echo "Auto counter reload sampling [Skipped not supported]"
> +    return
> +  fi
> +  if ! perf script -i "${perfdata}" | grep -q "period=20000,acr_mask=0x2"
> +  then
> +    echo "Auto counter reload sampling [Failed missing instructions event]"
> +    err=1
> +    return
> +  fi
> +  if perf script -i "${perfdata}" | grep -q "period=40000,acr_mask=0x3"
> +  then
> +    echo "Auto counter reload sampling [Failed cycles event shouldn't be sampled]"
> +    err=1
> +    return
> +  fi
> +  if ! perf record -o "${perfdata}" -e "${pebs_events}" ${testprog} 2> /dev/null
> +  then
> +    echo "Auto counter reload PEBS sampling [Skipped not supported]"
> +    return
> +  fi
> +  if ! perf script -i "${perfdata}" | grep -q "period=20000,acr_mask=0x2"
> +  then
> +    echo "Auto counter reload PEBS sampling [Failed missing instructions event]"
> +    err=1
> +    return
> +  fi
> +  if perf script -i "${perfdata}" | grep -q "period=40000,acr_mask=0x3"
> +  then
> +    echo "Auto counter reload PEBS sampling [Failed cycles event shouldn't be sampled]"
> +    err=1
> +    return
> +  fi
> +  echo "Auto counter reload sampling [Success]"

Thanks Dapeng! Could we also test ratio-to-prev as well as just the
plain acr_mask?

Thanks,
Ian

> +}
> +
>  test_ratio_to_prev() {
>    echo "ratio-to-prev test"
>    if ! perf record -o /dev/null -e "{instructions, cycles/period=100000,ratio-to-prev=0.5/}" \
> @@ -457,6 +498,7 @@ test_leader_sampling
>  test_topdown_leader_sampling
>  test_precise_max
>  test_callgraph
> +test_acr_sampling
>  test_ratio_to_prev
>
>  # restore the default value
>
> base-commit: 4e03d6494f9504f8af46ba68a2a8b6877c196789
> --
> 2.34.1
>

Re: [PATCH] perf tests: Add auto counter reload (ACR) sampling test

[Mi, Dapeng]

On 4/13/2026 9:30 AM, Ian Rogers wrote:
> On Sun, Apr 12, 2026 at 6:14 PM Dapeng Mi <dapeng1.mi@linux.intel.com> wrote:
>> Add auto counter reload sampling test to verify that the intended event
>> records can be captured and the self-reloaded events won't generate any
>> records.
>>
>> Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
>> ---
>>  tools/perf/tests/shell/record.sh | 42 ++++++++++++++++++++++++++++++++
>>  1 file changed, 42 insertions(+)
>>
>> diff --git a/tools/perf/tests/shell/record.sh b/tools/perf/tests/shell/record.sh
>> index 7cb81cf3444a..1068843282f5 100755
>> --- a/tools/perf/tests/shell/record.sh
>> +++ b/tools/perf/tests/shell/record.sh
>> @@ -402,6 +402,47 @@ test_callgraph() {
>>    echo "Callgraph test [Success]"
>>  }
>>
>> +test_acr_sampling() {
>> +  events="{instructions/period=20000,acr_mask=0x2/u,cycles/period=40000,acr_mask=0x3/u}"
>> +  pebs_events="{instructions/period=20000,acr_mask=0x2/pu,cycles/period=40000,acr_mask=0x3/u}"
>> +  echo "Auto counter reload sampling test"
>> +  if ! perf record -o "${perfdata}" -e "${events}" ${testprog} 2> /dev/null
>> +  then
>> +    echo "Auto counter reload sampling [Skipped not supported]"
>> +    return
>> +  fi
>> +  if ! perf script -i "${perfdata}" | grep -q "period=20000,acr_mask=0x2"
>> +  then
>> +    echo "Auto counter reload sampling [Failed missing instructions event]"
>> +    err=1
>> +    return
>> +  fi
>> +  if perf script -i "${perfdata}" | grep -q "period=40000,acr_mask=0x3"
>> +  then
>> +    echo "Auto counter reload sampling [Failed cycles event shouldn't be sampled]"
>> +    err=1
>> +    return
>> +  fi
>> +  if ! perf record -o "${perfdata}" -e "${pebs_events}" ${testprog} 2> /dev/null
>> +  then
>> +    echo "Auto counter reload PEBS sampling [Skipped not supported]"
>> +    return
>> +  fi
>> +  if ! perf script -i "${perfdata}" | grep -q "period=20000,acr_mask=0x2"
>> +  then
>> +    echo "Auto counter reload PEBS sampling [Failed missing instructions event]"
>> +    err=1
>> +    return
>> +  fi
>> +  if perf script -i "${perfdata}" | grep -q "period=40000,acr_mask=0x3"
>> +  then
>> +    echo "Auto counter reload PEBS sampling [Failed cycles event shouldn't be sampled]"
>> +    err=1
>> +    return
>> +  fi
>> +  echo "Auto counter reload sampling [Success]"
> Thanks Dapeng! Could we also test ratio-to-prev as well as just the
> plain acr_mask?

Good idea. Sure.


>
> Thanks,
> Ian
>
>> +}
>> +
>>  test_ratio_to_prev() {
>>    echo "ratio-to-prev test"
>>    if ! perf record -o /dev/null -e "{instructions, cycles/period=100000,ratio-to-prev=0.5/}" \
>> @@ -457,6 +498,7 @@ test_leader_sampling
>>  test_topdown_leader_sampling
>>  test_precise_max
>>  test_callgraph
>> +test_acr_sampling
>>  test_ratio_to_prev
>>
>>  # restore the default value
>>
>> base-commit: 4e03d6494f9504f8af46ba68a2a8b6877c196789
>> --
>> 2.34.1
>>

Re: [PATCH] perf tests: Add auto counter reload (ACR) sampling test

[Mi, Dapeng]

On 4/13/2026 9:26 AM, sashiko-bot@kernel.org wrote:
> Sashiko AI review found 1 potential issue(s):
> - [Medium] The test fails to genuinely verify that self-reloaded events do not generate records because the chosen sample periods and workload ensure the self-reloaded event never actually overflows.
> --
>
> commit 5e7a7e069f4c078327e3d8166d7f74d9084ec8a4
> Author: Dapeng Mi <dapeng1.mi@linux.intel.com>
>
> perf tests: Add auto counter reload (ACR) sampling test
>
> This commit adds an auto counter reload sampling test to verify that the
> intended event records can be captured and self-reloaded events do not
> generate any records.
>
>> diff --git a/tools/perf/tests/shell/record.sh b/tools/perf/tests/shell/record.sh
>> index 7cb81cf3444a7..1068843282f51 100755
>> --- a/tools/perf/tests/shell/record.sh
>> +++ b/tools/perf/tests/shell/record.sh
> [ ... ]
>> @@ -402,6 +402,47 @@ test_callgraph() {
>>    echo "Callgraph test [Success]"
>>  }
>>  
>> +test_acr_sampling() {
>> +  events="{instructions/period=20000,acr_mask=0x2/u,cycles/period=40000,acr_mask=0x3/u}"
>> +  pebs_events="{instructions/period=20000,acr_mask=0x2/pu,cycles/period=40000,acr_mask=0x3/u}"
> Does this test configuration actually verify that self-reloaded events do not
> generate records?
>
> The test runs the thloop workload, which is a tight CPU loop with an inherently
> high IPC (typically > 0.5). With periods of 20000 for instructions and 40000
> for cycles, the instructions event will always overflow first.

Hmm, makes sense. I would check the IPC of the thloop workload. Suppose
setting periods of both instructions and cycles to 20000 (IPC=1) could be a
better choice.

Thanks.

>
> When the instructions event overflows, its acr_mask=0x2 triggers an auto-reload
> of the cycles counter, resetting its progress toward overflow.
>
> Because it is continually reset by the instructions event before reaching
> 40000, the cycles counter never overflows.
>
> The test asserts that no records are generated for cycles and passes, but is
> this simply because the event never fired rather than due to self-reloaded PMI
> suppression working correctly?
>
> If the hardware PMI suppression for self-reloaded events was broken, wouldn't
> this test still pass?
>
> Additionally, if the test ran on a system with IPC < 0.5, wouldn't the cycles
> event overflow first, resetting both itself and instructions (acr_mask=0x3)?
> This would prevent instructions from generating a record, causing the test
> to fail.
>

Re: [PATCH] perf tests: Add auto counter reload (ACR) sampling test

[Mi, Dapeng]

On 4/13/2026 9:30 AM, Ian Rogers wrote:
> On Sun, Apr 12, 2026 at 6:14 PM Dapeng Mi <dapeng1.mi@linux.intel.com> wrote:
>> Add auto counter reload sampling test to verify that the intended event
>> records can be captured and the self-reloaded events won't generate any
>> records.
>>
>> Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
>> ---
>>  tools/perf/tests/shell/record.sh | 42 ++++++++++++++++++++++++++++++++
>>  1 file changed, 42 insertions(+)
>>
>> diff --git a/tools/perf/tests/shell/record.sh b/tools/perf/tests/shell/record.sh
>> index 7cb81cf3444a..1068843282f5 100755
>> --- a/tools/perf/tests/shell/record.sh
>> +++ b/tools/perf/tests/shell/record.sh
>> @@ -402,6 +402,47 @@ test_callgraph() {
>>    echo "Callgraph test [Success]"
>>  }
>>
>> +test_acr_sampling() {
>> +  events="{instructions/period=20000,acr_mask=0x2/u,cycles/period=40000,acr_mask=0x3/u}"
>> +  pebs_events="{instructions/period=20000,acr_mask=0x2/pu,cycles/period=40000,acr_mask=0x3/u}"
>> +  echo "Auto counter reload sampling test"
>> +  if ! perf record -o "${perfdata}" -e "${events}" ${testprog} 2> /dev/null
>> +  then
>> +    echo "Auto counter reload sampling [Skipped not supported]"
>> +    return
>> +  fi
>> +  if ! perf script -i "${perfdata}" | grep -q "period=20000,acr_mask=0x2"
>> +  then
>> +    echo "Auto counter reload sampling [Failed missing instructions event]"
>> +    err=1
>> +    return
>> +  fi
>> +  if perf script -i "${perfdata}" | grep -q "period=40000,acr_mask=0x3"
>> +  then
>> +    echo "Auto counter reload sampling [Failed cycles event shouldn't be sampled]"
>> +    err=1
>> +    return
>> +  fi
>> +  if ! perf record -o "${perfdata}" -e "${pebs_events}" ${testprog} 2> /dev/null
>> +  then
>> +    echo "Auto counter reload PEBS sampling [Skipped not supported]"
>> +    return
>> +  fi
>> +  if ! perf script -i "${perfdata}" | grep -q "period=20000,acr_mask=0x2"
>> +  then
>> +    echo "Auto counter reload PEBS sampling [Failed missing instructions event]"
>> +    err=1
>> +    return
>> +  fi
>> +  if perf script -i "${perfdata}" | grep -q "period=40000,acr_mask=0x3"
>> +  then
>> +    echo "Auto counter reload PEBS sampling [Failed cycles event shouldn't be sampled]"
>> +    err=1
>> +    return
>> +  fi
>> +  echo "Auto counter reload sampling [Success]"
> Thanks Dapeng! Could we also test ratio-to-prev as well as just the
> plain acr_mask?

Ian, it could be hard to validate ratio-to-prev option in this test. On
platforms which don't support ACR, perf would automatically fallback the
ACR sampling to normal sampling, this would lead to false positives on
checking the existence of records from cycles event. I didn't find a good
way to figure out this fallback.

Since we already have independent test case to validate the ratio_to_prev
parsing. It may be unnecessary to add ratio-to-prev validation in this ACR
test.


>
> Thanks,
> Ian
>
>> +}
>> +
>>  test_ratio_to_prev() {
>>    echo "ratio-to-prev test"
>>    if ! perf record -o /dev/null -e "{instructions, cycles/period=100000,ratio-to-prev=0.5/}" \
>> @@ -457,6 +498,7 @@ test_leader_sampling
>>  test_topdown_leader_sampling
>>  test_precise_max
>>  test_callgraph
>> +test_acr_sampling
>>  test_ratio_to_prev
>>
>>  # restore the default value
>>
>> base-commit: 4e03d6494f9504f8af46ba68a2a8b6877c196789
>> --
>> 2.34.1
>>

Re: [PATCH] perf tests: Add auto counter reload (ACR) sampling test

[Ian Rogers]

On Wed, Apr 15, 2026 at 2:19 AM Mi, Dapeng <dapeng1.mi@linux.intel.com> wrote:
>
>
> On 4/13/2026 9:30 AM, Ian Rogers wrote:
> > On Sun, Apr 12, 2026 at 6:14 PM Dapeng Mi <dapeng1.mi@linux.intel.com> wrote:
> >> Add auto counter reload sampling test to verify that the intended event
> >> records can be captured and the self-reloaded events won't generate any
> >> records.
> >>
> >> Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
> >> ---
> >>  tools/perf/tests/shell/record.sh | 42 ++++++++++++++++++++++++++++++++
> >>  1 file changed, 42 insertions(+)
> >>
> >> diff --git a/tools/perf/tests/shell/record.sh b/tools/perf/tests/shell/record.sh
> >> index 7cb81cf3444a..1068843282f5 100755
> >> --- a/tools/perf/tests/shell/record.sh
> >> +++ b/tools/perf/tests/shell/record.sh
> >> @@ -402,6 +402,47 @@ test_callgraph() {
> >>    echo "Callgraph test [Success]"
> >>  }
> >>
> >> +test_acr_sampling() {
> >> +  events="{instructions/period=20000,acr_mask=0x2/u,cycles/period=40000,acr_mask=0x3/u}"
> >> +  pebs_events="{instructions/period=20000,acr_mask=0x2/pu,cycles/period=40000,acr_mask=0x3/u}"
> >> +  echo "Auto counter reload sampling test"
> >> +  if ! perf record -o "${perfdata}" -e "${events}" ${testprog} 2> /dev/null
> >> +  then
> >> +    echo "Auto counter reload sampling [Skipped not supported]"
> >> +    return
> >> +  fi
> >> +  if ! perf script -i "${perfdata}" | grep -q "period=20000,acr_mask=0x2"
> >> +  then
> >> +    echo "Auto counter reload sampling [Failed missing instructions event]"
> >> +    err=1
> >> +    return
> >> +  fi
> >> +  if perf script -i "${perfdata}" | grep -q "period=40000,acr_mask=0x3"
> >> +  then
> >> +    echo "Auto counter reload sampling [Failed cycles event shouldn't be sampled]"
> >> +    err=1
> >> +    return
> >> +  fi
> >> +  if ! perf record -o "${perfdata}" -e "${pebs_events}" ${testprog} 2> /dev/null
> >> +  then
> >> +    echo "Auto counter reload PEBS sampling [Skipped not supported]"
> >> +    return
> >> +  fi
> >> +  if ! perf script -i "${perfdata}" | grep -q "period=20000,acr_mask=0x2"
> >> +  then
> >> +    echo "Auto counter reload PEBS sampling [Failed missing instructions event]"
> >> +    err=1
> >> +    return
> >> +  fi
> >> +  if perf script -i "${perfdata}" | grep -q "period=40000,acr_mask=0x3"
> >> +  then
> >> +    echo "Auto counter reload PEBS sampling [Failed cycles event shouldn't be sampled]"
> >> +    err=1
> >> +    return
> >> +  fi
> >> +  echo "Auto counter reload sampling [Success]"
> > Thanks Dapeng! Could we also test ratio-to-prev as well as just the
> > plain acr_mask?
>
> Ian, it could be hard to validate ratio-to-prev option in this test. On
> platforms which don't support ACR, perf would automatically fallback the
> ACR sampling to normal sampling, this would lead to false positives on
> checking the existence of records from cycles event. I didn't find a good
> way to figure out this fallback.
>
> Since we already have independent test case to validate the ratio_to_prev
> parsing. It may be unnecessary to add ratio-to-prev validation in this ACR
> test.

So the ratio_to_prev test covers parsing the ratio-to-prev option (it
only has `perf record` commands) and ensures it is acted upon, but it
doesn't check the option's functional behavior - what the output is.
This test makes sure the acr_mask option is functional and so would be
complemented by ratio-to-prev testing somethig like:
```
  rtp_events="{instructions,cycles/period=40000,ratio-to-prev=0.5/u}"

  # Test ratio-to-prev
  if ! perf record -o "${perfdata}" -e "${rtp_events}" ${testprog} 2> /dev/null
  then
    echo "Auto counter reload ratio-to-prev sampling [Failed record
ratio-to-prev]"
    err=1
    return
  fi
  if ! perf script -i "${perfdata}" | grep -q "instructions"
  then
    echo "Auto counter reload ratio-to-prev sampling [Failed missing
instructions event]"
    err=1
    return
  fi
  if perf script -i "${perfdata}" | grep -q "cycles"
  then
    echo "Auto counter reload ratio-to-prev sampling [Failed cycles
event shouldn't be sampled]"
    err=1
    return
  fi
```
The first thing your test does is to make sure the acr_mask is
supported, so I'm not sure how the fall back can happen?
We could additionally check for
`/sys/bus/event_source/devices/cpu*/format/acr_mask`.

Thanks,
Ian

> >
> > Thanks,
> > Ian
> >
> >> +}
> >> +
> >>  test_ratio_to_prev() {
> >>    echo "ratio-to-prev test"
> >>    if ! perf record -o /dev/null -e "{instructions, cycles/period=100000,ratio-to-prev=0.5/}" \
> >> @@ -457,6 +498,7 @@ test_leader_sampling
> >>  test_topdown_leader_sampling
> >>  test_precise_max
> >>  test_callgraph
> >> +test_acr_sampling
> >>  test_ratio_to_prev
> >>
> >>  # restore the default value
> >>
> >> base-commit: 4e03d6494f9504f8af46ba68a2a8b6877c196789
> >> --
> >> 2.34.1
> >>

Re: [PATCH] perf tests: Add auto counter reload (ACR) sampling test

[Mi, Dapeng]

On 4/16/2026 1:13 AM, Ian Rogers wrote:
> On Wed, Apr 15, 2026 at 2:19 AM Mi, Dapeng <dapeng1.mi@linux.intel.com> wrote:
>>
>> On 4/13/2026 9:30 AM, Ian Rogers wrote:
>>> On Sun, Apr 12, 2026 at 6:14 PM Dapeng Mi <dapeng1.mi@linux.intel.com> wrote:
>>>> Add auto counter reload sampling test to verify that the intended event
>>>> records can be captured and the self-reloaded events won't generate any
>>>> records.
>>>>
>>>> Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
>>>> ---
>>>>  tools/perf/tests/shell/record.sh | 42 ++++++++++++++++++++++++++++++++
>>>>  1 file changed, 42 insertions(+)
>>>>
>>>> diff --git a/tools/perf/tests/shell/record.sh b/tools/perf/tests/shell/record.sh
>>>> index 7cb81cf3444a..1068843282f5 100755
>>>> --- a/tools/perf/tests/shell/record.sh
>>>> +++ b/tools/perf/tests/shell/record.sh
>>>> @@ -402,6 +402,47 @@ test_callgraph() {
>>>>    echo "Callgraph test [Success]"
>>>>  }
>>>>
>>>> +test_acr_sampling() {
>>>> +  events="{instructions/period=20000,acr_mask=0x2/u,cycles/period=40000,acr_mask=0x3/u}"
>>>> +  pebs_events="{instructions/period=20000,acr_mask=0x2/pu,cycles/period=40000,acr_mask=0x3/u}"
>>>> +  echo "Auto counter reload sampling test"
>>>> +  if ! perf record -o "${perfdata}" -e "${events}" ${testprog} 2> /dev/null
>>>> +  then
>>>> +    echo "Auto counter reload sampling [Skipped not supported]"
>>>> +    return
>>>> +  fi
>>>> +  if ! perf script -i "${perfdata}" | grep -q "period=20000,acr_mask=0x2"
>>>> +  then
>>>> +    echo "Auto counter reload sampling [Failed missing instructions event]"
>>>> +    err=1
>>>> +    return
>>>> +  fi
>>>> +  if perf script -i "${perfdata}" | grep -q "period=40000,acr_mask=0x3"
>>>> +  then
>>>> +    echo "Auto counter reload sampling [Failed cycles event shouldn't be sampled]"
>>>> +    err=1
>>>> +    return
>>>> +  fi
>>>> +  if ! perf record -o "${perfdata}" -e "${pebs_events}" ${testprog} 2> /dev/null
>>>> +  then
>>>> +    echo "Auto counter reload PEBS sampling [Skipped not supported]"
>>>> +    return
>>>> +  fi
>>>> +  if ! perf script -i "${perfdata}" | grep -q "period=20000,acr_mask=0x2"
>>>> +  then
>>>> +    echo "Auto counter reload PEBS sampling [Failed missing instructions event]"
>>>> +    err=1
>>>> +    return
>>>> +  fi
>>>> +  if perf script -i "${perfdata}" | grep -q "period=40000,acr_mask=0x3"
>>>> +  then
>>>> +    echo "Auto counter reload PEBS sampling [Failed cycles event shouldn't be sampled]"
>>>> +    err=1
>>>> +    return
>>>> +  fi
>>>> +  echo "Auto counter reload sampling [Success]"
>>> Thanks Dapeng! Could we also test ratio-to-prev as well as just the
>>> plain acr_mask?
>> Ian, it could be hard to validate ratio-to-prev option in this test. On
>> platforms which don't support ACR, perf would automatically fallback the
>> ACR sampling to normal sampling, this would lead to false positives on
>> checking the existence of records from cycles event. I didn't find a good
>> way to figure out this fallback.
>>
>> Since we already have independent test case to validate the ratio_to_prev
>> parsing. It may be unnecessary to add ratio-to-prev validation in this ACR
>> test.
> So the ratio_to_prev test covers parsing the ratio-to-prev option (it
> only has `perf record` commands) and ensures it is acted upon, but it
> doesn't check the option's functional behavior - what the output is.
> This test makes sure the acr_mask option is functional and so would be
> complemented by ratio-to-prev testing somethig like:
> ```
>   rtp_events="{instructions,cycles/period=40000,ratio-to-prev=0.5/u}"
>
>   # Test ratio-to-prev
>   if ! perf record -o "${perfdata}" -e "${rtp_events}" ${testprog} 2> /dev/null
>   then
>     echo "Auto counter reload ratio-to-prev sampling [Failed record
> ratio-to-prev]"
>     err=1
>     return
>   fi
>   if ! perf script -i "${perfdata}" | grep -q "instructions"
>   then
>     echo "Auto counter reload ratio-to-prev sampling [Failed missing
> instructions event]"
>     err=1
>     return
>   fi
>   if perf script -i "${perfdata}" | grep -q "cycles"
>   then
>     echo "Auto counter reload ratio-to-prev sampling [Failed cycles
> event shouldn't be sampled]"
>     err=1
>     return
>   fi
> ```
> The first thing your test does is to make sure the acr_mask is
> supported, so I'm not sure how the fall back can happen?
> We could additionally check for
> `/sys/bus/event_source/devices/cpu*/format/acr_mask`.

Yes, that's initially what I intended to do, but it would cause false
positives on some hybrid platform, like PTL which only supports ACR on E-core.

```

$ grep . /sys/bus/event_source/devices/cpu_core/format/*
/sys/bus/event_source/devices/cpu_core/format/cmask:config:24-31
/sys/bus/event_source/devices/cpu_core/format/edge:config:18
/sys/bus/event_source/devices/cpu_core/format/eq:config:36
/sys/bus/event_source/devices/cpu_core/format/event:config:0-7
/sys/bus/event_source/devices/cpu_core/format/frontend:config1:0-23
/sys/bus/event_source/devices/cpu_core/format/inv:config:23
/sys/bus/event_source/devices/cpu_core/format/ldlat:config1:0-15
/sys/bus/event_source/devices/cpu_core/format/metrics_clear:config1:0
/sys/bus/event_source/devices/cpu_core/format/offcore_rsp:config1:0-63
/sys/bus/event_source/devices/cpu_core/format/pc:config:19
/sys/bus/event_source/devices/cpu_core/format/umask:config:8-15,40-47

$ grep . /sys/bus/event_source/devices/cpu_atom/format/*
/sys/bus/event_source/devices/cpu_atom/format/acr_mask:config2:0-63
/sys/bus/event_source/devices/cpu_atom/format/cmask:config:24-31
/sys/bus/event_source/devices/cpu_atom/format/edge:config:18
/sys/bus/event_source/devices/cpu_atom/format/eq:config:36
/sys/bus/event_source/devices/cpu_atom/format/event:config:0-7
/sys/bus/event_source/devices/cpu_atom/format/inv:config:23
/sys/bus/event_source/devices/cpu_atom/format/ldlat:config1:0-15
/sys/bus/event_source/devices/cpu_atom/format/offcore_rsp:config1:0-63
/sys/bus/event_source/devices/cpu_atom/format/pc:config:19
/sys/bus/event_source/devices/cpu_atom/format/snoop_rsp:config1:0-63
/sys/bus/event_source/devices/cpu_atom/format/umask:config:8-15,40-47

```

So strictly speaking, we need to check if it's a hybrid platform first and
then check if the exact P-core/E-core supports ACR, then run the above ACR
tests. It seems a little bit over-complicated and I'm not sure if it's
accepted to add so much Intel specific check in the record.sh.

How's your idea on this? Thanks.


>
> Thanks,
> Ian
>
>>> Thanks,
>>> Ian
>>>
>>>> +}
>>>> +
>>>>  test_ratio_to_prev() {
>>>>    echo "ratio-to-prev test"
>>>>    if ! perf record -o /dev/null -e "{instructions, cycles/period=100000,ratio-to-prev=0.5/}" \
>>>> @@ -457,6 +498,7 @@ test_leader_sampling
>>>>  test_topdown_leader_sampling
>>>>  test_precise_max
>>>>  test_callgraph
>>>> +test_acr_sampling
>>>>  test_ratio_to_prev
>>>>
>>>>  # restore the default value
>>>>
>>>> base-commit: 4e03d6494f9504f8af46ba68a2a8b6877c196789
>>>> --
>>>> 2.34.1
>>>>

Re: [PATCH] perf tests: Add auto counter reload (ACR) sampling test

[Ian Rogers]

On Wed, Apr 15, 2026 at 8:06 PM Mi, Dapeng <dapeng1.mi@linux.intel.com> wrote:
>
>
> On 4/16/2026 1:13 AM, Ian Rogers wrote:
> > On Wed, Apr 15, 2026 at 2:19 AM Mi, Dapeng <dapeng1.mi@linux.intel.com> wrote:
> >>
> >> On 4/13/2026 9:30 AM, Ian Rogers wrote:
> >>> On Sun, Apr 12, 2026 at 6:14 PM Dapeng Mi <dapeng1.mi@linux.intel.com> wrote:
> >>>> Add auto counter reload sampling test to verify that the intended event
> >>>> records can be captured and the self-reloaded events won't generate any
> >>>> records.
> >>>>
> >>>> Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
> >>>> ---
> >>>>  tools/perf/tests/shell/record.sh | 42 ++++++++++++++++++++++++++++++++
> >>>>  1 file changed, 42 insertions(+)
> >>>>
> >>>> diff --git a/tools/perf/tests/shell/record.sh b/tools/perf/tests/shell/record.sh
> >>>> index 7cb81cf3444a..1068843282f5 100755
> >>>> --- a/tools/perf/tests/shell/record.sh
> >>>> +++ b/tools/perf/tests/shell/record.sh
> >>>> @@ -402,6 +402,47 @@ test_callgraph() {
> >>>>    echo "Callgraph test [Success]"
> >>>>  }
> >>>>
> >>>> +test_acr_sampling() {
> >>>> +  events="{instructions/period=20000,acr_mask=0x2/u,cycles/period=40000,acr_mask=0x3/u}"
> >>>> +  pebs_events="{instructions/period=20000,acr_mask=0x2/pu,cycles/period=40000,acr_mask=0x3/u}"
> >>>> +  echo "Auto counter reload sampling test"
> >>>> +  if ! perf record -o "${perfdata}" -e "${events}" ${testprog} 2> /dev/null
> >>>> +  then
> >>>> +    echo "Auto counter reload sampling [Skipped not supported]"
> >>>> +    return
> >>>> +  fi
> >>>> +  if ! perf script -i "${perfdata}" | grep -q "period=20000,acr_mask=0x2"
> >>>> +  then
> >>>> +    echo "Auto counter reload sampling [Failed missing instructions event]"
> >>>> +    err=1
> >>>> +    return
> >>>> +  fi
> >>>> +  if perf script -i "${perfdata}" | grep -q "period=40000,acr_mask=0x3"
> >>>> +  then
> >>>> +    echo "Auto counter reload sampling [Failed cycles event shouldn't be sampled]"
> >>>> +    err=1
> >>>> +    return
> >>>> +  fi
> >>>> +  if ! perf record -o "${perfdata}" -e "${pebs_events}" ${testprog} 2> /dev/null
> >>>> +  then
> >>>> +    echo "Auto counter reload PEBS sampling [Skipped not supported]"
> >>>> +    return
> >>>> +  fi
> >>>> +  if ! perf script -i "${perfdata}" | grep -q "period=20000,acr_mask=0x2"
> >>>> +  then
> >>>> +    echo "Auto counter reload PEBS sampling [Failed missing instructions event]"
> >>>> +    err=1
> >>>> +    return
> >>>> +  fi
> >>>> +  if perf script -i "${perfdata}" | grep -q "period=40000,acr_mask=0x3"
> >>>> +  then
> >>>> +    echo "Auto counter reload PEBS sampling [Failed cycles event shouldn't be sampled]"
> >>>> +    err=1
> >>>> +    return
> >>>> +  fi
> >>>> +  echo "Auto counter reload sampling [Success]"
> >>> Thanks Dapeng! Could we also test ratio-to-prev as well as just the
> >>> plain acr_mask?
> >> Ian, it could be hard to validate ratio-to-prev option in this test. On
> >> platforms which don't support ACR, perf would automatically fallback the
> >> ACR sampling to normal sampling, this would lead to false positives on
> >> checking the existence of records from cycles event. I didn't find a good
> >> way to figure out this fallback.
> >>
> >> Since we already have independent test case to validate the ratio_to_prev
> >> parsing. It may be unnecessary to add ratio-to-prev validation in this ACR
> >> test.
> > So the ratio_to_prev test covers parsing the ratio-to-prev option (it
> > only has `perf record` commands) and ensures it is acted upon, but it
> > doesn't check the option's functional behavior - what the output is.
> > This test makes sure the acr_mask option is functional and so would be
> > complemented by ratio-to-prev testing somethig like:
> > ```
> >   rtp_events="{instructions,cycles/period=40000,ratio-to-prev=0.5/u}"
> >
> >   # Test ratio-to-prev
> >   if ! perf record -o "${perfdata}" -e "${rtp_events}" ${testprog} 2> /dev/null
> >   then
> >     echo "Auto counter reload ratio-to-prev sampling [Failed record
> > ratio-to-prev]"
> >     err=1
> >     return
> >   fi
> >   if ! perf script -i "${perfdata}" | grep -q "instructions"
> >   then
> >     echo "Auto counter reload ratio-to-prev sampling [Failed missing
> > instructions event]"
> >     err=1
> >     return
> >   fi
> >   if perf script -i "${perfdata}" | grep -q "cycles"
> >   then
> >     echo "Auto counter reload ratio-to-prev sampling [Failed cycles
> > event shouldn't be sampled]"
> >     err=1
> >     return
> >   fi
> > ```
> > The first thing your test does is to make sure the acr_mask is
> > supported, so I'm not sure how the fall back can happen?
> > We could additionally check for
> > `/sys/bus/event_source/devices/cpu*/format/acr_mask`.
>
> Yes, that's initially what I intended to do, but it would cause false
> positives on some hybrid platform, like PTL which only supports ACR on E-core.
>
> ```
>
> $ grep . /sys/bus/event_source/devices/cpu_core/format/*
> /sys/bus/event_source/devices/cpu_core/format/cmask:config:24-31
> /sys/bus/event_source/devices/cpu_core/format/edge:config:18
> /sys/bus/event_source/devices/cpu_core/format/eq:config:36
> /sys/bus/event_source/devices/cpu_core/format/event:config:0-7
> /sys/bus/event_source/devices/cpu_core/format/frontend:config1:0-23
> /sys/bus/event_source/devices/cpu_core/format/inv:config:23
> /sys/bus/event_source/devices/cpu_core/format/ldlat:config1:0-15
> /sys/bus/event_source/devices/cpu_core/format/metrics_clear:config1:0
> /sys/bus/event_source/devices/cpu_core/format/offcore_rsp:config1:0-63
> /sys/bus/event_source/devices/cpu_core/format/pc:config:19
> /sys/bus/event_source/devices/cpu_core/format/umask:config:8-15,40-47
>
> $ grep . /sys/bus/event_source/devices/cpu_atom/format/*
> /sys/bus/event_source/devices/cpu_atom/format/acr_mask:config2:0-63
> /sys/bus/event_source/devices/cpu_atom/format/cmask:config:24-31
> /sys/bus/event_source/devices/cpu_atom/format/edge:config:18
> /sys/bus/event_source/devices/cpu_atom/format/eq:config:36
> /sys/bus/event_source/devices/cpu_atom/format/event:config:0-7
> /sys/bus/event_source/devices/cpu_atom/format/inv:config:23
> /sys/bus/event_source/devices/cpu_atom/format/ldlat:config1:0-15
> /sys/bus/event_source/devices/cpu_atom/format/offcore_rsp:config1:0-63
> /sys/bus/event_source/devices/cpu_atom/format/pc:config:19
> /sys/bus/event_source/devices/cpu_atom/format/snoop_rsp:config1:0-63
> /sys/bus/event_source/devices/cpu_atom/format/umask:config:8-15,40-47
>
> ```
>
> So strictly speaking, we need to check if it's a hybrid platform first and
> then check if the exact P-core/E-core supports ACR, then run the above ACR
> tests. It seems a little bit over-complicated and I'm not sure if it's
> accepted to add so much Intel specific check in the record.sh.
>
> How's your idea on this? Thanks.

Potentially auto counter reload and ratio to prev are generic
concepts, it just happens that we only have Intel e-core
implementations :-) Matching against cpu* already misses ARM core
PMUs. I'm always happy for as much testing as possible. The last code
coverage number I have for Linux v6.17 is 38.6% of lines under
tools/perf. Since then, I've added quite a bit of testing for commands
like `perf top`. Perhaps we now cover over 50% of the lines of code.

Thanks,
Ian

> >
> > Thanks,
> > Ian
> >
> >>> Thanks,
> >>> Ian
> >>>
> >>>> +}
> >>>> +
> >>>>  test_ratio_to_prev() {
> >>>>    echo "ratio-to-prev test"
> >>>>    if ! perf record -o /dev/null -e "{instructions, cycles/period=100000,ratio-to-prev=0.5/}" \
> >>>> @@ -457,6 +498,7 @@ test_leader_sampling
> >>>>  test_topdown_leader_sampling
> >>>>  test_precise_max
> >>>>  test_callgraph
> >>>> +test_acr_sampling
> >>>>  test_ratio_to_prev
> >>>>
> >>>>  # restore the default value
> >>>>
> >>>> base-commit: 4e03d6494f9504f8af46ba68a2a8b6877c196789
> >>>> --
> >>>> 2.34.1
> >>>>

Re: [PATCH] perf tests: Add auto counter reload (ACR) sampling test

[Mi, Dapeng]

On 4/16/2026 11:17 AM, Ian Rogers wrote:
> On Wed, Apr 15, 2026 at 8:06 PM Mi, Dapeng <dapeng1.mi@linux.intel.com> wrote:
>>
>> On 4/16/2026 1:13 AM, Ian Rogers wrote:
>>> On Wed, Apr 15, 2026 at 2:19 AM Mi, Dapeng <dapeng1.mi@linux.intel.com> wrote:
>>>> On 4/13/2026 9:30 AM, Ian Rogers wrote:
>>>>> On Sun, Apr 12, 2026 at 6:14 PM Dapeng Mi <dapeng1.mi@linux.intel.com> wrote:
>>>>>> Add auto counter reload sampling test to verify that the intended event
>>>>>> records can be captured and the self-reloaded events won't generate any
>>>>>> records.
>>>>>>
>>>>>> Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
>>>>>> ---
>>>>>>  tools/perf/tests/shell/record.sh | 42 ++++++++++++++++++++++++++++++++
>>>>>>  1 file changed, 42 insertions(+)
>>>>>>
>>>>>> diff --git a/tools/perf/tests/shell/record.sh b/tools/perf/tests/shell/record.sh
>>>>>> index 7cb81cf3444a..1068843282f5 100755
>>>>>> --- a/tools/perf/tests/shell/record.sh
>>>>>> +++ b/tools/perf/tests/shell/record.sh
>>>>>> @@ -402,6 +402,47 @@ test_callgraph() {
>>>>>>    echo "Callgraph test [Success]"
>>>>>>  }
>>>>>>
>>>>>> +test_acr_sampling() {
>>>>>> +  events="{instructions/period=20000,acr_mask=0x2/u,cycles/period=40000,acr_mask=0x3/u}"
>>>>>> +  pebs_events="{instructions/period=20000,acr_mask=0x2/pu,cycles/period=40000,acr_mask=0x3/u}"
>>>>>> +  echo "Auto counter reload sampling test"
>>>>>> +  if ! perf record -o "${perfdata}" -e "${events}" ${testprog} 2> /dev/null
>>>>>> +  then
>>>>>> +    echo "Auto counter reload sampling [Skipped not supported]"
>>>>>> +    return
>>>>>> +  fi
>>>>>> +  if ! perf script -i "${perfdata}" | grep -q "period=20000,acr_mask=0x2"
>>>>>> +  then
>>>>>> +    echo "Auto counter reload sampling [Failed missing instructions event]"
>>>>>> +    err=1
>>>>>> +    return
>>>>>> +  fi
>>>>>> +  if perf script -i "${perfdata}" | grep -q "period=40000,acr_mask=0x3"
>>>>>> +  then
>>>>>> +    echo "Auto counter reload sampling [Failed cycles event shouldn't be sampled]"
>>>>>> +    err=1
>>>>>> +    return
>>>>>> +  fi
>>>>>> +  if ! perf record -o "${perfdata}" -e "${pebs_events}" ${testprog} 2> /dev/null
>>>>>> +  then
>>>>>> +    echo "Auto counter reload PEBS sampling [Skipped not supported]"
>>>>>> +    return
>>>>>> +  fi
>>>>>> +  if ! perf script -i "${perfdata}" | grep -q "period=20000,acr_mask=0x2"
>>>>>> +  then
>>>>>> +    echo "Auto counter reload PEBS sampling [Failed missing instructions event]"
>>>>>> +    err=1
>>>>>> +    return
>>>>>> +  fi
>>>>>> +  if perf script -i "${perfdata}" | grep -q "period=40000,acr_mask=0x3"
>>>>>> +  then
>>>>>> +    echo "Auto counter reload PEBS sampling [Failed cycles event shouldn't be sampled]"
>>>>>> +    err=1
>>>>>> +    return
>>>>>> +  fi
>>>>>> +  echo "Auto counter reload sampling [Success]"
>>>>> Thanks Dapeng! Could we also test ratio-to-prev as well as just the
>>>>> plain acr_mask?
>>>> Ian, it could be hard to validate ratio-to-prev option in this test. On
>>>> platforms which don't support ACR, perf would automatically fallback the
>>>> ACR sampling to normal sampling, this would lead to false positives on
>>>> checking the existence of records from cycles event. I didn't find a good
>>>> way to figure out this fallback.
>>>>
>>>> Since we already have independent test case to validate the ratio_to_prev
>>>> parsing. It may be unnecessary to add ratio-to-prev validation in this ACR
>>>> test.
>>> So the ratio_to_prev test covers parsing the ratio-to-prev option (it
>>> only has `perf record` commands) and ensures it is acted upon, but it
>>> doesn't check the option's functional behavior - what the output is.
>>> This test makes sure the acr_mask option is functional and so would be
>>> complemented by ratio-to-prev testing somethig like:
>>> ```
>>>   rtp_events="{instructions,cycles/period=40000,ratio-to-prev=0.5/u}"
>>>
>>>   # Test ratio-to-prev
>>>   if ! perf record -o "${perfdata}" -e "${rtp_events}" ${testprog} 2> /dev/null
>>>   then
>>>     echo "Auto counter reload ratio-to-prev sampling [Failed record
>>> ratio-to-prev]"
>>>     err=1
>>>     return
>>>   fi
>>>   if ! perf script -i "${perfdata}" | grep -q "instructions"
>>>   then
>>>     echo "Auto counter reload ratio-to-prev sampling [Failed missing
>>> instructions event]"
>>>     err=1
>>>     return
>>>   fi
>>>   if perf script -i "${perfdata}" | grep -q "cycles"
>>>   then
>>>     echo "Auto counter reload ratio-to-prev sampling [Failed cycles
>>> event shouldn't be sampled]"
>>>     err=1
>>>     return
>>>   fi
>>> ```
>>> The first thing your test does is to make sure the acr_mask is
>>> supported, so I'm not sure how the fall back can happen?
>>> We could additionally check for
>>> `/sys/bus/event_source/devices/cpu*/format/acr_mask`.
>> Yes, that's initially what I intended to do, but it would cause false
>> positives on some hybrid platform, like PTL which only supports ACR on E-core.
>>
>> ```
>>
>> $ grep . /sys/bus/event_source/devices/cpu_core/format/*
>> /sys/bus/event_source/devices/cpu_core/format/cmask:config:24-31
>> /sys/bus/event_source/devices/cpu_core/format/edge:config:18
>> /sys/bus/event_source/devices/cpu_core/format/eq:config:36
>> /sys/bus/event_source/devices/cpu_core/format/event:config:0-7
>> /sys/bus/event_source/devices/cpu_core/format/frontend:config1:0-23
>> /sys/bus/event_source/devices/cpu_core/format/inv:config:23
>> /sys/bus/event_source/devices/cpu_core/format/ldlat:config1:0-15
>> /sys/bus/event_source/devices/cpu_core/format/metrics_clear:config1:0
>> /sys/bus/event_source/devices/cpu_core/format/offcore_rsp:config1:0-63
>> /sys/bus/event_source/devices/cpu_core/format/pc:config:19
>> /sys/bus/event_source/devices/cpu_core/format/umask:config:8-15,40-47
>>
>> $ grep . /sys/bus/event_source/devices/cpu_atom/format/*
>> /sys/bus/event_source/devices/cpu_atom/format/acr_mask:config2:0-63
>> /sys/bus/event_source/devices/cpu_atom/format/cmask:config:24-31
>> /sys/bus/event_source/devices/cpu_atom/format/edge:config:18
>> /sys/bus/event_source/devices/cpu_atom/format/eq:config:36
>> /sys/bus/event_source/devices/cpu_atom/format/event:config:0-7
>> /sys/bus/event_source/devices/cpu_atom/format/inv:config:23
>> /sys/bus/event_source/devices/cpu_atom/format/ldlat:config1:0-15
>> /sys/bus/event_source/devices/cpu_atom/format/offcore_rsp:config1:0-63
>> /sys/bus/event_source/devices/cpu_atom/format/pc:config:19
>> /sys/bus/event_source/devices/cpu_atom/format/snoop_rsp:config1:0-63
>> /sys/bus/event_source/devices/cpu_atom/format/umask:config:8-15,40-47
>>
>> ```
>>
>> So strictly speaking, we need to check if it's a hybrid platform first and
>> then check if the exact P-core/E-core supports ACR, then run the above ACR
>> tests. It seems a little bit over-complicated and I'm not sure if it's
>> accepted to add so much Intel specific check in the record.sh.
>>
>> How's your idea on this? Thanks.
> Potentially auto counter reload and ratio to prev are generic
> concepts, it just happens that we only have Intel e-core
> implementations :-) Matching against cpu* already misses ARM core
> PMUs. I'm always happy for as much testing as possible. The last code
> coverage number I have for Linux v6.17 is 38.6% of lines under
> tools/perf. Since then, I've added quite a bit of testing for commands
> like `perf top`. Perhaps we now cover over 50% of the lines of code.

Ok, incomplete tests are always better than no tests. I would add the test
although it looks not so pretty. :)


>
> Thanks,
> Ian
>
>>> Thanks,
>>> Ian
>>>
>>>>> Thanks,
>>>>> Ian
>>>>>
>>>>>> +}
>>>>>> +
>>>>>>  test_ratio_to_prev() {
>>>>>>    echo "ratio-to-prev test"
>>>>>>    if ! perf record -o /dev/null -e "{instructions, cycles/period=100000,ratio-to-prev=0.5/}" \
>>>>>> @@ -457,6 +498,7 @@ test_leader_sampling
>>>>>>  test_topdown_leader_sampling
>>>>>>  test_precise_max
>>>>>>  test_callgraph
>>>>>> +test_acr_sampling
>>>>>>  test_ratio_to_prev
>>>>>>
>>>>>>  # restore the default value
>>>>>>
>>>>>> base-commit: 4e03d6494f9504f8af46ba68a2a8b6877c196789
>>>>>> --
>>>>>> 2.34.1
>>>>>>