[PATCH] perf test: Fix test perf stat tests for virtualized machines

Thomas Richter posted 1 patch 1 month ago
There is a newer version of this series
tools/perf/tests/shell/stat.sh | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
[PATCH] perf test: Fix test perf stat tests for virtualized machines
Posted by Thomas Richter 1 month ago
On s390 perf test 'perf stat tests', subtest test_hybrid fails
for z/VM systems.
The root cause is this statement:

  $(perf stat -a -- sleep 0.1 2>&1 |\
                  grep -E "/cpu-cycles/[uH]*|  cpu-cycles[:uH]* -c)

The perf stat output on a s390 z/VM system is

 # perf stat -a -- sleep 0.1 2>&1
 Performance counter stats for 'system wide':

       56      context-switches  #     46.3 cs/sec  cs_per_second
 1,210.41 msec cpu-clock         #     11.9 CPUs  CPUs_utilized
       12      cpu-migrations    #      9.9 migrations/sec ...
       81      page-faults       #     66.9 faults/sec ...

       0.100891009 seconds time elapsed

The grep command does not match any single line and exits with error
code 1. As the bash script is executed with set -e, it aborts with the
first error code being non-zero.

Fix this and use wc -l to count matching lines instead of grep ... -c.

Output before:
 # perf test 102
 102: perf stat tests                      : FAILED!
 #
Output after:
 # perf test 102
 102: perf stat tests                      : Ok
 #

Fixes: 65d11821910bd ("perf test: Add a test for default perf stat command")
Cc: James Clark <james.clark@linaro.org>
Cc: Ian Rogers <irogers@google.com>
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
---
 tools/perf/tests/shell/stat.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/tests/shell/stat.sh b/tools/perf/tests/shell/stat.sh
index 0b2f0f88ca16..792a0b79f6b8 100755
--- a/tools/perf/tests/shell/stat.sh
+++ b/tools/perf/tests/shell/stat.sh
@@ -233,7 +233,7 @@ test_hybrid() {
   fi
 
   # Run default Perf stat
-  cycles_events=$(perf stat -a -- sleep 0.1 2>&1 | grep -E "/cpu-cycles/[uH]*|  cpu-cycles[:uH]*  " -c)
+  cycles_events=$(perf stat -a -- sleep 0.1 2>&1 | grep -E "/cpu-cycles/[uH]*|  cpu-cycles[:uH]*  "  | wc -l)
 
   # The expectation is that default output will have a cycles events on each
   # hybrid PMU. In situations with no cycles PMU events, like virtualized, this
-- 
2.52.0
Re: [PATCH] perf test: Fix test perf stat tests for virtualized machines
Posted by James Clark 1 month ago

On 07/01/2026 9:48 am, Thomas Richter wrote:
> On s390 perf test 'perf stat tests', subtest test_hybrid fails
> for z/VM systems.
> The root cause is this statement:
> 
>    $(perf stat -a -- sleep 0.1 2>&1 |\
>                    grep -E "/cpu-cycles/[uH]*|  cpu-cycles[:uH]* -c)
> 
> The perf stat output on a s390 z/VM system is
> 
>   # perf stat -a -- sleep 0.1 2>&1
>   Performance counter stats for 'system wide':
> 
>         56      context-switches  #     46.3 cs/sec  cs_per_second
>   1,210.41 msec cpu-clock         #     11.9 CPUs  CPUs_utilized
>         12      cpu-migrations    #      9.9 migrations/sec ...
>         81      page-faults       #     66.9 faults/sec ...
> 
>         0.100891009 seconds time elapsed
> 
> The grep command does not match any single line and exits with error
> code 1. As the bash script is executed with set -e, it aborts with the
> first error code being non-zero.
> 
> Fix this and use wc -l to count matching lines instead of grep ... -c.
> 
> Output before:
>   # perf test 102
>   102: perf stat tests                      : FAILED!
>   #
> Output after:
>   # perf test 102
>   102: perf stat tests                      : Ok
>   #
> 
> Fixes: 65d11821910bd ("perf test: Add a test for default perf stat command")

I think the change looks ok, but doesn't it fix 65d11821910bd ("perf 
tools: Add fallback for exclude_guest") where the existing wc -l was 
changed to grep -c?

> Cc: James Clark <james.clark@linaro.org>
> Cc: Ian Rogers <irogers@google.com>
> Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
> ---
>   tools/perf/tests/shell/stat.sh | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/tools/perf/tests/shell/stat.sh b/tools/perf/tests/shell/stat.sh
> index 0b2f0f88ca16..792a0b79f6b8 100755
> --- a/tools/perf/tests/shell/stat.sh
> +++ b/tools/perf/tests/shell/stat.sh
> @@ -233,7 +233,7 @@ test_hybrid() {
>     fi
>   
>     # Run default Perf stat
> -  cycles_events=$(perf stat -a -- sleep 0.1 2>&1 | grep -E "/cpu-cycles/[uH]*|  cpu-cycles[:uH]*  " -c)
> +  cycles_events=$(perf stat -a -- sleep 0.1 2>&1 | grep -E "/cpu-cycles/[uH]*|  cpu-cycles[:uH]*  "  | wc -l)
>   
>     # The expectation is that default output will have a cycles events on each
>     # hybrid PMU. In situations with no cycles PMU events, like virtualized, this
Re: [PATCH] perf test: Fix test perf stat tests for virtualized machines
Posted by Thomas Richter 1 month ago
On 1/7/26 12:18, James Clark wrote:
> 
> 
> On 07/01/2026 9:48 am, Thomas Richter wrote:
>> On s390 perf test 'perf stat tests', subtest test_hybrid fails
>> for z/VM systems.
>> The root cause is this statement:
>>
>>    $(perf stat -a -- sleep 0.1 2>&1 |\
>>                    grep -E "/cpu-cycles/[uH]*|  cpu-cycles[:uH]* -c)
>>
>> The perf stat output on a s390 z/VM system is
>>
>>   # perf stat -a -- sleep 0.1 2>&1
>>   Performance counter stats for 'system wide':
>>
>>         56      context-switches  #     46.3 cs/sec  cs_per_second
>>   1,210.41 msec cpu-clock         #     11.9 CPUs  CPUs_utilized
>>         12      cpu-migrations    #      9.9 migrations/sec ...
>>         81      page-faults       #     66.9 faults/sec ...
>>
>>         0.100891009 seconds time elapsed
>>
>> The grep command does not match any single line and exits with error
>> code 1. As the bash script is executed with set -e, it aborts with the
>> first error code being non-zero.
>>
>> Fix this and use wc -l to count matching lines instead of grep ... -c.
>>
>> Output before:
>>   # perf test 102
>>   102: perf stat tests                      : FAILED!
>>   #
>> Output after:
>>   # perf test 102
>>   102: perf stat tests                      : Ok
>>   #
>>
>> Fixes: 65d11821910bd ("perf test: Add a test for default perf stat command")
> 
> I think the change looks ok, but doesn't it fix 65d11821910bd ("perf tools: Add fallback for exclude_guest") where the existing wc -l was changed to grep -c?
> 

You are correct, James.
I will send V2 with updated Fixes tag.

Thanks
-- 
Thomas Richter, Dept 3303, IBM s390 Linux Development, Boeblingen, Germany
--
IBM Deutschland Research & Development GmbH

Vorsitzender des Aufsichtsrats: Wolfgang Wendt

Geschäftsführung: David Faller

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