Bug 111925

The CI Bug Log issue associated to this bug has been updated.

### New filters associated

* SNB BYT HSW: igt@gem_eio@in-flight-contexts-immediate|igt@gem_eio@in-flight-contexts-10ms - fail - Failed assertion: igt_seconds_elapsed(&ts) <= 10
  - https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_7011/shard-snb7/igt@gem_eio@in-flight-contexts-immediate.html
  - https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_14671/shard-snb1/igt@gem_eio@in-flight-contexts-immediate.html
  - https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_14677/shard-snb4/igt@gem_eio@in-flight-contexts-immediate.html
  - https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_7012/shard-hsw4/igt@gem_eio@in-flight-contexts-10ms.html
  - https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_7012/shard-snb2/igt@gem_eio@in-flight-contexts-immediate.html
  - https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_14678/shard-snb2/igt@gem_eio@in-flight-contexts-immediate.html
  - https://intel-gfx-ci.01.org/tree/drm-tip/drmtip_384/fi-byt-j1900/igt@gem_eio@in-flight-contexts-10ms.html
  - https://intel-gfx-ci.01.org/tree/drm-tip/drmtip_384/fi-snb-2600/igt@gem_eio@in-flight-contexts-immediate.html
  - https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_14681/shard-snb6/igt@gem_eio@in-flight-contexts-immediate.html
  - https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_7021/shard-snb6/igt@gem_eio@in-flight-contexts-immediate.html
  - https://intel-gfx-ci.01.org/tree/drm-tip/IGTPW_3544/shard-snb4/igt@gem_eio@in-flight-contexts-immediate.html
  - https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_7024/shard-snb7/igt@gem_eio@in-flight-contexts-immediate.html
  - https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_14686/shard-snb6/igt@gem_eio@in-flight-contexts-immediate.html
  - https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_7026/shard-hsw6/igt@gem_eio@in-flight-contexts-10ms.html
  - https://intel-gfx-ci.01.org/tree/drm-tip/IGTPW_3550/shard-snb1/igt@gem_eio@in-flight-contexts-immediate.html
  - https://intel-gfx-ci.01.org/tree/drm-tip/IGTPW_3552/shard-snb7/igt@gem_eio@in-flight-contexts-immediate.html

Hopefully,

commit 998e29e137444db6e0ec2c65611a7eab3e0b6a21
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Mon Oct 7 09:26:28 2019 +0100

    lib/i915: Bump conservative threshold for ring size
    
    We are still hitting the occasional stall upon submission, so be extra
    caution and leave one more spare.
    
    Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
    Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

Still happening
https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_7124/shard-snb2/igt@gem_eio@in-flight-contexts-immediate.html
Starting subtest: in-flight-contexts-immediate
(gem_eio:4019) CRITICAL: Test assertion failure function trigger_reset, file ../tests/i915/gem_eio.c:90:
(gem_eio:4019) CRITICAL: Failed assertion: igt_seconds_elapsed(&ts) <= 10
(gem_eio:4019) CRITICAL: error: 21 > 10
Subtest in-flight-contexts-immediate failed.

A CI Bug Log filter associated to this bug has been updated:

{- SNB BYT HSW: igt@gem_eio@in-flight-contexts-immediate|igt@gem_eio@in-flight-contexts-10ms - fail - Failed assertion: igt_seconds_elapsed(&ts) <= 10 -}
{+ SNB BYT HSW: igt@gem_eio@in-flight-contexts-immediate|igt@gem_eio@in-flight-contexts-10ms|igt@gem_eio@in-flight-contexts-1us - fail - Failed assertion: igt_seconds_elapsed(&ts) <= 10 +}

New failures caught by the filter:

  * https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_7125/shard-snb4/igt@gem_eio@in-flight-contexts-1us.html

Minor issue according to Chris.

Next installment of this saga,
commit a64a29e775443e869e4524e5bd3a3427225810dc (upstream/master)
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Mon Nov 11 11:36:34 2019 +0000

    i915/gem_eio: Flush RCU before timing our own critical sections
    
    We cannot control how long RCU takes to find a quiescent point as that
    depends upon the background load and so may take an arbitrary time.
    Instead, let's try to avoid that impacting our measurements by inserting
    an rcu_barrier() before our critical timing sections and hope that hides
    the issue, letting us always perform a fast reset. Fwiw, we do the
    expedited RCU synchronize, but that is not always enough.
    
    Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
    Acked-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>

Let's be brave and like all the other times assume that this fixes it for real.