[Intel-gfx] [PATCH] drm/i915: Reduce i915_request.lock contention for i915_request_wait

[Tvrtko Ursulin]

On 16/07/2020 09:47, Chris Wilson wrote:
> Quoting Tvrtko Ursulin (2020-07-16 09:41:17)
>> Right I missed dma_fence_is_signaled calls i915_request_completed.
>>
>> In this case the remaining question is do we care about wait ioctl
>> potentially returning before the hypothetical sync fence for the same
>> request is signaled? This seems like a slight change in user observable
>> behaviour.
> 
> You would not be able to observe the difference after wakeup in state
> between a sync_file and busy_ioctl/wait_ioctl, as a query after wakeup
> will see the same signaled bit. So the only possible difference is a
> change in wakeup order; but process wakeup/execution order is definitely
> not defined by us :)

Doh.. true, same vfunc..

Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>

Regards,

Tvrtko