[PATCH V2] perf test: Fix test perf stat tests for virtualized machines

[PATCH V2] perf test: Fix test perf stat tests for virtualized machines

[Thomas Richter]

V1 --> V2: Add correct Fixes: tag, suggested by James Clark

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: bb6e7cb11d97c ("perf tools: Add fallback for exclude_guest")
Cc: James Clark <james.clark@linaro.org>
Cc: Ian Rogers <irogers@google.com>
Cc: Namhyung Kim <namhyung@kernel.org>
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 V2] perf test: Fix test perf stat tests for virtualized machines

[James Clark]

On 07/01/2026 1:32 pm, Thomas Richter wrote:
> V1 --> V2: Add correct Fixes: tag, suggested by James Clark
> 
> On s390 perf test 'perf stat tests', subtest test_hybrid fails
> for z/VM systems.
> The root cause is this statement:
> 
>    $(perf stat -a -- sleep 0.1 2>&1 |\
>                    grep -E "/cpu-cycles/[uH]*|  cpu-cycles[:uH]* -c)
> 
> The perf stat output on a s390 z/VM system is
> 
>   # perf stat -a -- sleep 0.1 2>&1
>   Performance counter stats for 'system wide':
> 
>         56      context-switches  #     46.3 cs/sec  cs_per_second
>   1,210.41 msec cpu-clock         #     11.9 CPUs  CPUs_utilized
>         12      cpu-migrations    #      9.9 migrations/sec ...
>         81      page-faults       #     66.9 faults/sec ...
> 
>         0.100891009 seconds time elapsed
> 
> The grep command does not match any single line and exits with error
> code 1. As the bash script is executed with set -e, it aborts with the
> first error code being non-zero.
> 
> Fix this and use wc -l to count matching lines instead of grep ... -c.
> 
> Output before:
>   # perf test 102
>   102: perf stat tests                      : FAILED!
>   #
> Output after:
>   # perf test 102
>   102: perf stat tests                      : Ok
>   #
> 
> Fixes: bb6e7cb11d97c ("perf tools: Add fallback for exclude_guest")
> Cc: James Clark <james.clark@linaro.org>
> Cc: Ian Rogers <irogers@google.com>
> Cc: Namhyung Kim <namhyung@kernel.org>
> Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
> ---
>   tools/perf/tests/shell/stat.sh | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/tools/perf/tests/shell/stat.sh b/tools/perf/tests/shell/stat.sh
> index 0b2f0f88ca16..792a0b79f6b8 100755
> --- a/tools/perf/tests/shell/stat.sh
> +++ b/tools/perf/tests/shell/stat.sh
> @@ -233,7 +233,7 @@ test_hybrid() {
>     fi
>   
>     # Run default Perf stat
> -  cycles_events=$(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

Reviewed-by: James Clark <james.clark@linaro.org>

Re: [PATCH V2] perf test: Fix test perf stat tests for virtualized machines

[Ian Rogers]

On Wed, Jan 7, 2026 at 7:30 AM James Clark <james.clark@linaro.org> wrote:
>
>
>
> On 07/01/2026 1:32 pm, Thomas Richter wrote:
> > V1 --> V2: Add correct Fixes: tag, suggested by James Clark
> >
> > On s390 perf test 'perf stat tests', subtest test_hybrid fails
> > for z/VM systems.
> > The root cause is this statement:
> >
> >    $(perf stat -a -- sleep 0.1 2>&1 |\
> >                    grep -E "/cpu-cycles/[uH]*|  cpu-cycles[:uH]* -c)
> >
> > The perf stat output on a s390 z/VM system is
> >
> >   # perf stat -a -- sleep 0.1 2>&1
> >   Performance counter stats for 'system wide':
> >
> >         56      context-switches  #     46.3 cs/sec  cs_per_second
> >   1,210.41 msec cpu-clock         #     11.9 CPUs  CPUs_utilized
> >         12      cpu-migrations    #      9.9 migrations/sec ...
> >         81      page-faults       #     66.9 faults/sec ...
> >
> >         0.100891009 seconds time elapsed
> >
> > The grep command does not match any single line and exits with error
> > code 1. As the bash script is executed with set -e, it aborts with the
> > first error code being non-zero.
> >
> > Fix this and use wc -l to count matching lines instead of grep ... -c.
> >
> > Output before:
> >   # perf test 102
> >   102: perf stat tests                      : FAILED!
> >   #
> > Output after:
> >   # perf test 102
> >   102: perf stat tests                      : Ok
> >   #
> >
> > Fixes: bb6e7cb11d97c ("perf tools: Add fallback for exclude_guest")
> > Cc: James Clark <james.clark@linaro.org>
> > Cc: Ian Rogers <irogers@google.com>
> > Cc: Namhyung Kim <namhyung@kernel.org>
> > Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
> > ---
> >   tools/perf/tests/shell/stat.sh | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/tools/perf/tests/shell/stat.sh b/tools/perf/tests/shell/stat.sh
> > index 0b2f0f88ca16..792a0b79f6b8 100755
> > --- a/tools/perf/tests/shell/stat.sh
> > +++ b/tools/perf/tests/shell/stat.sh
> > @@ -233,7 +233,7 @@ test_hybrid() {
> >     fi
> >
> >     # Run default Perf stat
> > -  cycles_events=$(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
>
> Reviewed-by: James Clark <james.clark@linaro.org>

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

Thanks,
Ian

Re: [PATCH V2] perf test: Fix test perf stat tests for virtualized machines

[Arnaldo Carvalho de Melo]

On Thu, Jan 08, 2026 at 10:03:49AM -0800, Ian Rogers wrote:
> On Wed, Jan 7, 2026 at 7:30 AM James Clark <james.clark@linaro.org> wrote:
> > On 07/01/2026 1:32 pm, Thomas Richter wrote:
> > >     # 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

> > Reviewed-by: James Clark <james.clark@linaro.org>
 
> Reviewed-by: Ian Rogers <irogers@google.com>

Thanks, applied to perf-tools-next,

- Arnaldo