[Intel-gfx] [PATCH] drm/i915/gt: Only delay the barrier pm

[Tvrtko Ursulin]

On 23/03/2020 19:20, Chris Wilson wrote:
> It is strictly sufficient to only delay the intel_engine_pm_put from the
> context barrier (and not from the context exit) in order to prevent the
> gem_exec_nop contention. Adding the delay to the context exit incurs
> noticably extra penalty for soft-rc6.
> 
> Fixes: edee52c927ef ("drm/i915/gt: Delay release of engine-pm after last retirement")
> Testcase: igt/i915_pm_rc6_residency/rc6-idle
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> ---
>   drivers/gpu/drm/i915/gt/intel_context.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/gt/intel_context.c b/drivers/gpu/drm/i915/gt/intel_context.c
> index 622ff425fce9..e4aece20bc80 100644
> --- a/drivers/gpu/drm/i915/gt/intel_context.c
> +++ b/drivers/gpu/drm/i915/gt/intel_context.c
> @@ -350,7 +350,7 @@ void intel_context_enter_engine(struct intel_context *ce)
>   void intel_context_exit_engine(struct intel_context *ce)
>   {
>   	intel_timeline_exit(ce->timeline);
> -	intel_engine_pm_put_delay(ce->engine, 1);
> +	intel_engine_pm_put(ce->engine);
>   }
>   
>   int intel_context_prepare_remote_request(struct intel_context *ce,
> 

I wanted to ask during review about the effect on soft rc6 but thought 
you looked at it.

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

Regards,

Tvrtko