Hi Kamil,

On Wednesday, 8 October 2025 18:42:42 CEST Kamil Konieczny wrote:
> Hi Janusz,
> On 2025-10-08 at 14:52:44 +0200, Janusz Krzysztofik wrote:
> > Hi Kamil,
> > 
> > On Wednesday, 8 October 2025 14:14:47 CEST Kamil Konieczny wrote:
> > > Hi Janusz,
> > > On 2025-10-07 at 13:38:25 +0200, Janusz Krzysztofik wrote:
> > > > Subtests that measure time of resume after engine reset require results
> > > > from at least 9 reset-resume cycles for reasonable calculation of a 
> > > > median
> > > > value to be compared against a presumed limit.  On most Gen12+ 
> > > > platforms,
> > > > as well as on some older ones like JSL, CHV, ILK or ELK, the current 
> > > > limit
> > > > of 5 seconds for collecting those results occurs too short.
> > > > 
> > > > Raise the limit to an empirically determined value of 20 seconds and 
> > > > break
> > > > the loop as soon as 9 results are collected.
> > > > 
> > > > v2: Split out a change in handling of not enough measurements to a
> > > >     separate patch (Kamil),
> > > >   - reword commit message to be more distinct from other patches in
> > > >     series (Kamil),
> > > >   - reword commit message and description so they no longer state the
> > > >     scope of the issue is limited to Gen12+, and list other (non-Gen12+)
> > > >     platforms found also affected.
> > > > 
> > > > Signed-off-by: Janusz Krzysztofik <[email protected]>
> > > > ---
> > > >  tests/intel/gem_eio.c | 5 ++++-
> > > >  1 file changed, 4 insertions(+), 1 deletion(-)
> > > > 
> > > > diff --git a/tests/intel/gem_eio.c b/tests/intel/gem_eio.c
> > > > index 0a00ef026e..79dcef8fa6 100644
> > > > --- a/tests/intel/gem_eio.c
> > > > +++ b/tests/intel/gem_eio.c
> > > > @@ -929,7 +929,7 @@ static void reset_stress(int fd, uint64_t ahnd, 
> > > > const 
> > intel_ctx_t *ctx0,
> > > >         gem_write(fd, obj.handle, 0, &bbe, sizeof(bbe));
> > > >  
> > > >         igt_stats_init(&stats);
> > > > -       igt_until_timeout(5) {
> > > > +       igt_until_timeout(20) {
> > > 
> > > What I wanted here was actually (in pseudocode):
> > > 
> > > mtime = gen < 5 || gen >= 12 ? 20 : 5;
> > 
> > That's incorrect.  JSL, now mentioned in commit description (see also 
> > changelog), is gen11, and it's the only one of that gen that exhibits the 
> > problem.  Moreover, some affected CI machines need more time in 
> > unwedge-stress 
> > and not necessarily in reset-stress, some vice versa, and still some need 
> > more 
> > time in both.  That may sound strange, but that's how results from my many 
> > trybot attempts look like.  Also, not all pre-gen5 machines require a 
> > higher 
> > limit on resume time, as it is handled now and extended over gen12+ in next 
> > patch.  So before I try to fulfil your expectation and use a formula here, 
> > not 
> > a constant, we have to agree on how much precise that formula should be.  
> > If 
> > you don't accept a simplified approach then I have to spend more time on 
> > finding out what exactly takes time on kernel side in each of those 
> > distinct 
> > cases and maybe then I will be able to formulate exact conditions when we 
> > should wait longer and when not.
> > 
> 
> One more note - maybe it is related with two GTs: GT0 and GT1?

Maybe, but that's only one of potential factors, not covering cases like DG2 
or ILK as an example of two cases completely different, I believe.

> 
> It could go with simplified formula here and just use some value,
> 20 or 10?

I still don't understand what your goal here is.  What issue do you expect to 
be avoided or resolved by replacing the new, higher constant value with a 
formula?  If I understood your point than I should be able to propose a 
solution.

> 
> Btw did you see results for v1? The gem_eio@kms subtests
> is failing due to disk limit in CI, and in logs there are
> 21 'Forcing GPU reset' messages.
> 
> https://intel-gfx-ci.01.org/tree/drm-tip/IGTPW_13866/shard-dg2-5/igt@[email protected]
> https://intel-gfx-ci.01.org/tree/drm-tip/IGTPW_13866/shard-tglu-8/igt@[email protected]
> 
> Is it not related to your series?

Yes, that's related, in the sense that before, there was a shorter, 5s limit 
for performing resets and measuring resume time, so less noise was accumulated 
in dmesg than now when we wait up to 20s for 9 measurements collected in order 
to avoid falsely reporting success when we don't evaluate results because less 
than 9 have been collected.

> Maybe number of resets should also be lowered?

The kms subtest consist of 3 exercises.  The first one -- inflight -- triggers 
7 resets (1 reset per ring), the remaining two ones are equivalents of reset-
stress and unwedge-stress, with 9 resets per each of the 2 scenarios required 
as a minimum for stable median calculation, so 25 resets in total.

Are you sure we are free to lower that limit of 9 measurements required for 
stable median?

I think we should rather convince CI and display developers to limit the 
amount of noise in dmesg generated in CI runs by display debugging.

> Also test took over 20 seconds after it was killed.

I can see "Disk usage limit exceeded" event reported at timestamp 340.998570, 
and next subtest scheduled at 342.958470.  Where do you see those 20 seconds?

Thanks,
Janusz


> 
> Regards,
> Kamil
> 
> > > 
> > >   igt_until_timeout(mtime) {
> > > 
> > > >                 const intel_ctx_t *ctx = context_create_safe(fd);
> > > >                 igt_spin_t *hang;
> > > >                 unsigned int i;
> > > > @@ -978,6 +978,9 @@ static void reset_stress(int fd, uint64_t ahnd, 
> > > > const 
> > intel_ctx_t *ctx0,
> > > >                 gem_sync(fd, obj.handle);
> > > >                 igt_spin_free(fd, hang);
> > > >                 intel_ctx_destroy(fd, ctx);
> > > > +
> > > > +               if (stats.n_values > 8)
> > > 
> > > Can it be a define as it is used in other places, for example:
> > > #define NUMER_OF_MEASURED_CYCLES_NEEDED 9
> > > 
> > > so you will use it elsewhere, and here it will be:
> > > 
> > >           if (stats.n_values >= NUMER_OF_MEASURED_CYCLES_NEEDED)
> > >                   break;
> > 
> > OK.
> > 
> > > 
> > > >         }
> > > >         check_wait_elapsed(name, fd, &stats);
> > > 
> > > I did give you r-b for patch 1/5 but I am not sure how
> > > reliable are measurements, should it be an assert instead of skip?
> > > Maybe function check_wait_elapsed() should return bool to tell if
> > > median is ready, and in each place subtests itself decide if it
> > > should skip or assert? Up to you.
> > 
> > check_wait_elapsed() is called only from reset_stress(), which in turn is 
> > called only by 3 subtests, all in scope of this series.  Can you suggest 
> > some 
> > criteria when you think a subtest should skip and when it should fail if 
> > not 
> > enough results have been collected?  I've chosen skip because we couldn't 
> > do 
> > much with fail other than blocklisting the failing subtest, while CI can 
> > handle skips as expected skips on selected platforms if we really can't 
> > find 
> > a balance among the loop long enough for collecting enough measurements and 
> > short enough for not exceeding per test timeout on platforms with many 
> > engines.
> > 
> > Thanks,
> > Janusz
> > 
> > 
> > > 
> > > Regards,
> > > Kamil
> > > 
> > > >         igt_stats_fini(&stats);
> > > 
> > 
> > 
> > 
> > 
> 




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