[PATCH] drm/i915/selftests: Wait longer for request to start

[PATCH] drm/i915/selftests: Wait longer for request to start

[Janusz Krzysztofik]

CI extreamly sporadically (five times over last six mohths) reported
failures of igt@i915_selftest@live@hangcheck on ARL-S machines.  The
selftest was timing out while waiting up to 1 second for a request
supposed to trigger a GPU hang to be started.  It occurred possible to
reproduce this issue manually by running the selftest in a loop for a
few hours.

Among results from 5 occurrences reported by CI so far, and two manual
reproductions, two of them contained messages that suggested a
posssibility of the awaited request to actually start soon after
timeout.  With the timeout extended from 1 to 2 seconds, it occurred no
longer possible to trigger the failure, even when running the test in a
loop for 10, then for 12 hours, on the same machine where it was failing
before in 2-3 hours.

Assume the conditions that prevented the hang requests to start within 1
second were always transient, and 2 seconds is sufficient for those
requests to start effectively on machines in the CI environment.  Fix
the issue by using that value as the timeout.

Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/work_items/16624
Signed-off-by: Janusz Krzysztofik <janusz.krzysztofik@linux.intel.com>
---
 drivers/gpu/drm/i915/gt/selftest_hangcheck.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gt/selftest_hangcheck.c b/drivers/gpu/drm/i915/gt/selftest_hangcheck.c
index 00dfc37221fac..53f3ce5c33a47 100644
--- a/drivers/gpu/drm/i915/gt/selftest_hangcheck.c
+++ b/drivers/gpu/drm/i915/gt/selftest_hangcheck.c
@@ -278,7 +278,7 @@ static bool wait_until_running(struct hang *h, struct i915_request *rq)
 			     10) &&
 		 wait_for(i915_seqno_passed(hws_seqno(h, rq),
 					    rq->fence.seqno),
-			  1000));
+			  2000));
 }
 
 static int igt_hang_sanitycheck(void *arg)
-- 
2.54.0

✗ Fi.CI.BUILD: failure for drm/i915/selftests: Wait longer for request to start

[Patchwork]

== Series Details ==

Series: drm/i915/selftests: Wait longer for request to start
URL   : https://patchwork.freedesktop.org/series/173050/
State : failure

== Summary ==

Applying: drm/i915/selftests: Wait longer for request to start
Patch failed at 0001 drm/i915/selftests: Wait longer for request to start
When you have resolved this problem, run "git am --continue".
If you prefer to skip this patch, run "git am --skip" instead.
To restore the original branch and stop patching, run "git am --abort".

Re: [PATCH] drm/i915/selftests: Wait longer for request to start

[Krzysztof Karas]

Hi Janusz,

On 2026-08-31 at 11:33:08 +0200, Janusz Krzysztofik wrote:
> CI extreamly sporadically (five times over last six mohths) reported
extreamly -> extremely, mohths -> months

> failures of igt@i915_selftest@live@hangcheck on ARL-S machines.  The
> selftest was timing out while waiting up to 1 second for a request
> supposed to trigger a GPU hang to be started.  It occurred possible to
> reproduce this issue manually by running the selftest in a loop for a
> few hours.
> 
> Among results from 5 occurrences reported by CI so far, and two manual
> reproductions, two of them contained messages that suggested a
> posssibility of the awaited request to actually start soon after
> timeout.  With the timeout extended from 1 to 2 seconds, it occurred no
> longer possible to trigger the failure, even when running the test in a
> loop for 10, then for 12 hours, on the same machine where it was failing
> before in 2-3 hours.
> 
> Assume the conditions that prevented the hang requests to start within 1
> second were always transient, and 2 seconds is sufficient for those
> requests to start effectively on machines in the CI environment.  Fix
> the issue by using that value as the timeout.
> 
> Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/work_items/16624
> Signed-off-by: Janusz Krzysztofik <janusz.krzysztofik@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/gt/selftest_hangcheck.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/gt/selftest_hangcheck.c b/drivers/gpu/drm/i915/gt/selftest_hangcheck.c
> index 00dfc37221fac..53f3ce5c33a47 100644
> --- a/drivers/gpu/drm/i915/gt/selftest_hangcheck.c
> +++ b/drivers/gpu/drm/i915/gt/selftest_hangcheck.c
> @@ -278,7 +278,7 @@ static bool wait_until_running(struct hang *h, struct i915_request *rq)
>  			     10) &&
>  		 wait_for(i915_seqno_passed(hws_seqno(h, rq),
>  					    rq->fence.seqno),
> -			  1000));
> +			  2000));
>  }
>  
>  static int igt_hang_sanitycheck(void *arg)
> -- 
> 2.54.0
> 

Patch is trivial, so:
Reviewed-by: Krzysztof Karas <krzysztof.karas@intel.com>

though, it would probably need a rebase, since it does not apply
cleanly for CI build process.

-- 
Best Regards,
Krzysztof

Re: [PATCH] drm/i915/selftests: Wait longer for request to start

[Janusz Krzysztofik]

Hi Krzysztof,

On Tue, 2026-09-01 at 06:19 +0000, Krzysztof Karas wrote:
> Hi Janusz,
> 
> On 2026-08-31 at 11:33:08 +0200, Janusz Krzysztofik wrote:
> > CI extreamly sporadically (five times over last six mohths) reported
> extreamly -> extremely, mohths -> months

Heh, thanks, those were results of my last minute polishing, apparently
with spell checker off, sorry.

> 
> > failures of igt@i915_selftest@live@hangcheck on ARL-S machines.  The
> > selftest was timing out while waiting up to 1 second for a request
> > supposed to trigger a GPU hang to be started.  It occurred possible to
> > reproduce this issue manually by running the selftest in a loop for a
> > few hours.
> > 
> > Among results from 5 occurrences reported by CI so far, and two manual
> > reproductions, two of them contained messages that suggested a
> > posssibility of the awaited request to actually start soon after
> > timeout.  With the timeout extended from 1 to 2 seconds, it occurred no
> > longer possible to trigger the failure, even when running the test in a
> > loop for 10, then for 12 hours, on the same machine where it was failing
> > before in 2-3 hours.
> > 
> > Assume the conditions that prevented the hang requests to start within 1
> > second were always transient, and 2 seconds is sufficient for those
> > requests to start effectively on machines in the CI environment.  Fix
> > the issue by using that value as the timeout.
> > 
> > Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/work_items/16624
> > Signed-off-by: Janusz Krzysztofik <janusz.krzysztofik@linux.intel.com>
> > ---
> >  drivers/gpu/drm/i915/gt/selftest_hangcheck.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/gt/selftest_hangcheck.c b/drivers/gpu/drm/i915/gt/selftest_hangcheck.c
> > index 00dfc37221fac..53f3ce5c33a47 100644
> > --- a/drivers/gpu/drm/i915/gt/selftest_hangcheck.c
> > +++ b/drivers/gpu/drm/i915/gt/selftest_hangcheck.c
> > @@ -278,7 +278,7 @@ static bool wait_until_running(struct hang *h, struct i915_request *rq)
> >  			     10) &&
> >  		 wait_for(i915_seqno_passed(hws_seqno(h, rq),
> >  					    rq->fence.seqno),
> > -			  1000));
> > +			  2000));
> >  }
> >  
> >  static int igt_hang_sanitycheck(void *arg)
> > -- 
> > 2.54.0
> > 
> 
> Patch is trivial, so:
> Reviewed-by: Krzysztof Karas <krzysztof.karas@intel.com>

Thank you :-)

> 
> though, it would probably need a rebase, since it does not apply
> cleanly for CI build process.

Please note that was only a response from an attempt to apply the patch to
IGT sources (I sent a copy to igt-dev@lists.freedesktop.org).

Thanks,
Janusz

Re: [PATCH] drm/i915/selftests: Wait longer for request to start

[Krzysztof Niemiec]

On 2026-08-31 at 11:33:08 +0200, Janusz Krzysztofik wrote:
> CI extreamly sporadically (five times over last six mohths) reported
> failures of igt@i915_selftest@live@hangcheck on ARL-S machines.  The
> selftest was timing out while waiting up to 1 second for a request
> supposed to trigger a GPU hang to be started.  It occurred possible to
> reproduce this issue manually by running the selftest in a loop for a
> few hours.
> 
> Among results from 5 occurrences reported by CI so far, and two manual
> reproductions, two of them contained messages that suggested a
> posssibility of the awaited request to actually start soon after
> timeout.  With the timeout extended from 1 to 2 seconds, it occurred no
> longer possible to trigger the failure, even when running the test in a
> loop for 10, then for 12 hours, on the same machine where it was failing
> before in 2-3 hours.
> 
> Assume the conditions that prevented the hang requests to start within 1
> second were always transient, and 2 seconds is sufficient for those
> requests to start effectively on machines in the CI environment.  Fix
> the issue by using that value as the timeout.
> 

What's the median request start time under usual conditions? It's
interesting to me why a timeout of 1s doesn't capture all occurences but
2s seems to do so. If the usual start time is on the order of few
hundred ms, then it's very possible maybe 90% of requests start within
1s and CI just exposes the 10% via large numbers. But if the start time
is usually ~10ms or ~1ms, is there some slowpath that triggers from time to
time that is expected to take on the order of ~100ms or ~1s? Or maybe a
scheduling, or power issue?

This patch does no harm and gets CI scripts to shut up about an otherwise
working test. But there is a world where the CI fails are exposing some
very subtle bug (though I sincerely doubt it's any urgent or worth going
out of your way to fix)

Otherwise with the Krzysztof Karas's comments about commit log:

Reviewed-by: Krzysztof Niemiec <krzysztof.niemiec@intel.com>

Thanks
Krzysztof

Re: [PATCH] drm/i915/selftests: Wait longer for request to start

[Andi Shyti]

Hi Janusz,

On Mon, Aug 31, 2026 at 11:33:08AM +0200, Janusz Krzysztofik wrote:
> CI extreamly sporadically (five times over last six mohths) reported
> failures of igt@i915_selftest@live@hangcheck on ARL-S machines.  The
> selftest was timing out while waiting up to 1 second for a request
> supposed to trigger a GPU hang to be started.  It occurred possible to
> reproduce this issue manually by running the selftest in a loop for a
> few hours.
> 
> Among results from 5 occurrences reported by CI so far, and two manual
> reproductions, two of them contained messages that suggested a
> posssibility of the awaited request to actually start soon after
> timeout.  With the timeout extended from 1 to 2 seconds, it occurred no
> longer possible to trigger the failure, even when running the test in a
> loop for 10, then for 12 hours, on the same machine where it was failing
> before in 2-3 hours.
> 
> Assume the conditions that prevented the hang requests to start within 1
> second were always transient, and 2 seconds is sufficient for those
> requests to start effectively on machines in the CI environment.  Fix
> the issue by using that value as the timeout.
> 
> Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/work_items/16624
> Signed-off-by: Janusz Krzysztofik <janusz.krzysztofik@linux.intel.com>

reviewed and pushed to drm-intel-gt-next.

Thanks,
Andi