[PATCH 0/2] drm/syncobj: add syncobj sideband payload for threaded submission

[Lionel Landwerlin]

Hi,

The goal of this feature is to solve an issue that was seen in our
testing. After discussing on [1] I thought we could solve this problem
with stalling the application thread after each vkQueueSubmit() call
where a binary semaphore is signaled but I don't think it's a good
option because of performance impacts on the application.

Unfortunately there isn't a good way to reproduce this problem 100%
because it essentially exposes a race between the application thread
and the submission thread.

I've uploaded tests in the Khronos repository to try to expose the
issue.

Thanks,

[1] : https://lists.freedesktop.org/archives/dri-devel/2019-August/229188.html

Lionel Landwerlin (2):
  drm/syncobj: add sideband payload
  drm/syncobj: add submit point query capability

 drivers/gpu/drm/drm_syncobj.c | 132 ++++++++++++++++++++++------------
 include/drm/drm_syncobj.h     |   9 +++
 include/uapi/drm/drm.h        |   5 +-
 3 files changed, 100 insertions(+), 46 deletions(-)

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2.23.0.rc1