[PATCH] perf test: Compile named_threads workload with -O0

[PATCH] perf test: Compile named_threads workload with -O0

[James Clark]

The work loop relies on the compiler not optimizing it away, although
named_threads_work is not static for that reason, the compiler could
still do it.

Fix it by compiling without optimization. Also add -fno-inline for
consistency and in case anyone wants to look at callstacks.

Signed-off-by: James Clark <james.clark@linaro.org>
---
One trailing Sashiko fix from the "perf cs-etm: Queue context packets
for frontend" patch series that has been applied already.
---
 tools/perf/tests/workloads/Build | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/perf/tests/workloads/Build b/tools/perf/tests/workloads/Build
index 75b377934a0e..7bb4b9829ba2 100644
--- a/tools/perf/tests/workloads/Build
+++ b/tools/perf/tests/workloads/Build
@@ -26,3 +26,4 @@ CFLAGS_datasym.o          = -g -O0 -fno-inline -U_FORTIFY_SOURCE
 CFLAGS_traploop.o         = -g -O0 -fno-inline -U_FORTIFY_SOURCE
 CFLAGS_inlineloop.o       = -g -O2
 CFLAGS_deterministic.o    = -g -O0 -fno-inline -U_FORTIFY_SOURCE
+CFLAGS_named_threads.o    = -g -O0 -fno-inline -U_FORTIFY_SOURCE

---
base-commit: 7336514f41e75d44782fee7e0990d4195a3d3161
change-id: 20260611-james-cs-unformatted-per-thread-fix-followup-babf28a4e640

Best regards,
-- 
James Clark <james.clark@linaro.org>

Re: [PATCH] perf test: Compile named_threads workload with -O0

[Leo Yan]

On Thu, Jun 11, 2026 at 12:13:46PM +0100, James Clark wrote:
> The work loop relies on the compiler not optimizing it away, although
> named_threads_work is not static for that reason, the compiler could
> still do it.
> 
> Fix it by compiling without optimization. Also add -fno-inline for
> consistency and in case anyone wants to look at callstacks.
> 
> Signed-off-by: James Clark <james.clark@linaro.org>

Reviewed-by: Leo Yan <leo.yan@arm.com>

Re: [PATCH] perf test: Compile named_threads workload with -O0

[Arnaldo Carvalho de Melo]

On Thu, Jun 11, 2026 at 12:13:46PM +0100, James Clark wrote:
> The work loop relies on the compiler not optimizing it away, although
> named_threads_work is not static for that reason, the compiler could
> still do it.
> 
> Fix it by compiling without optimization. Also add -fno-inline for
> consistency and in case anyone wants to look at callstacks.
> 
> Signed-off-by: James Clark <james.clark@linaro.org>
> ---
> One trailing Sashiko fix from the "perf cs-etm: Queue context packets
> for frontend" patch series that has been applied already.

I'll add a Fixes tag pointing to that cset, also a reported-by sashiko
and a closes, for completeness.

Thanks, applying.

- Arnaldo

> ---
>  tools/perf/tests/workloads/Build | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/tools/perf/tests/workloads/Build b/tools/perf/tests/workloads/Build
> index 75b377934a0e..7bb4b9829ba2 100644
> --- a/tools/perf/tests/workloads/Build
> +++ b/tools/perf/tests/workloads/Build
> @@ -26,3 +26,4 @@ CFLAGS_datasym.o          = -g -O0 -fno-inline -U_FORTIFY_SOURCE
>  CFLAGS_traploop.o         = -g -O0 -fno-inline -U_FORTIFY_SOURCE
>  CFLAGS_inlineloop.o       = -g -O2
>  CFLAGS_deterministic.o    = -g -O0 -fno-inline -U_FORTIFY_SOURCE
> +CFLAGS_named_threads.o    = -g -O0 -fno-inline -U_FORTIFY_SOURCE
> 
> ---
> base-commit: 7336514f41e75d44782fee7e0990d4195a3d3161
> change-id: 20260611-james-cs-unformatted-per-thread-fix-followup-babf28a4e640
> 
> Best regards,
> -- 
> James Clark <james.clark@linaro.org>

Re: [PATCH] perf test: Compile named_threads workload with -O0

[James Clark]

On 11/06/2026 4:08 pm, Arnaldo Carvalho de Melo wrote:
> On Thu, Jun 11, 2026 at 12:13:46PM +0100, James Clark wrote:
>> The work loop relies on the compiler not optimizing it away, although
>> named_threads_work is not static for that reason, the compiler could
>> still do it.
>>
>> Fix it by compiling without optimization. Also add -fno-inline for
>> consistency and in case anyone wants to look at callstacks.
>>
>> Signed-off-by: James Clark <james.clark@linaro.org>
>> ---
>> One trailing Sashiko fix from the "perf cs-etm: Queue context packets
>> for frontend" patch series that has been applied already.
> 
> I'll add a Fixes tag pointing to that cset, also a reported-by sashiko
> and a closes, for completeness.
> 
> Thanks, applying.
> 
> - Arnaldo
> 

Thanks, makes sense yeah. I probably could have been a bit more thorough.

>> ---
>>   tools/perf/tests/workloads/Build | 1 +
>>   1 file changed, 1 insertion(+)
>>
>> diff --git a/tools/perf/tests/workloads/Build b/tools/perf/tests/workloads/Build
>> index 75b377934a0e..7bb4b9829ba2 100644
>> --- a/tools/perf/tests/workloads/Build
>> +++ b/tools/perf/tests/workloads/Build
>> @@ -26,3 +26,4 @@ CFLAGS_datasym.o          = -g -O0 -fno-inline -U_FORTIFY_SOURCE
>>   CFLAGS_traploop.o         = -g -O0 -fno-inline -U_FORTIFY_SOURCE
>>   CFLAGS_inlineloop.o       = -g -O2
>>   CFLAGS_deterministic.o    = -g -O0 -fno-inline -U_FORTIFY_SOURCE
>> +CFLAGS_named_threads.o    = -g -O0 -fno-inline -U_FORTIFY_SOURCE
>>
>> ---
>> base-commit: 7336514f41e75d44782fee7e0990d4195a3d3161
>> change-id: 20260611-james-cs-unformatted-per-thread-fix-followup-babf28a4e640
>>
>> Best regards,
>> -- 
>> James Clark <james.clark@linaro.org>

Re: [PATCH] perf test: Compile named_threads workload with -O0

[David Laight]

On Thu, 11 Jun 2026 12:13:46 +0100
James Clark <james.clark@linaro.org> wrote:

> The work loop relies on the compiler not optimizing it away, although
> named_threads_work is not static for that reason, the compiler could
> still do it.

Isn't in enough to put barrier() in the loop?

	David

> 
> Fix it by compiling without optimization. Also add -fno-inline for
> consistency and in case anyone wants to look at callstacks.
> 
> Signed-off-by: James Clark <james.clark@linaro.org>
> ---
> One trailing Sashiko fix from the "perf cs-etm: Queue context packets
> for frontend" patch series that has been applied already.
> ---
>  tools/perf/tests/workloads/Build | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/tools/perf/tests/workloads/Build b/tools/perf/tests/workloads/Build
> index 75b377934a0e..7bb4b9829ba2 100644
> --- a/tools/perf/tests/workloads/Build
> +++ b/tools/perf/tests/workloads/Build
> @@ -26,3 +26,4 @@ CFLAGS_datasym.o          = -g -O0 -fno-inline -U_FORTIFY_SOURCE
>  CFLAGS_traploop.o         = -g -O0 -fno-inline -U_FORTIFY_SOURCE
>  CFLAGS_inlineloop.o       = -g -O2
>  CFLAGS_deterministic.o    = -g -O0 -fno-inline -U_FORTIFY_SOURCE
> +CFLAGS_named_threads.o    = -g -O0 -fno-inline -U_FORTIFY_SOURCE
> 
> ---
> base-commit: 7336514f41e75d44782fee7e0990d4195a3d3161
> change-id: 20260611-james-cs-unformatted-per-thread-fix-followup-babf28a4e640
> 
> Best regards,