[Intel-gfx] [PATCH 07/70] drm/i915: Boost GPU frequency if we detect outstanding pageflips

[Daniel Vetter]

On Tue, Apr 07, 2015 at 04:20:31PM +0100, Chris Wilson wrote:
> If we hit a vblank and see that have a pageflip queue but not yet
> processed, ensure that the GPU is running at maximum in order to clear
> the backlog. Pageflips are only queued for the following vblank, if we
> miss it, there will be a visible stutter. Boosting the GPU frequency
> doesn't prevent us from missing the target vblank, but it should help
> the subsequent frames hitting theirs.
> 
> v2: Reorder vblank vs flip-complete so that we only check for a missed
> flip after processing the completion events, and avoid spurious boosts.
> 
> v3: Rename missed_vblank
> v4: Rebase
> v5: Cancel the outstanding work in runtime suspend
> v6: Rebase
> v7: Rebase required fixing
> 
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> Cc: Deepak S<deepak.s at linux.intel.com>

This one also had an r-b from Deepak already, I applied all the rps tuning
patches from this series.

Thanks, Daniel

> ---
>  drivers/gpu/drm/i915/intel_display.c | 11 ++++++++---
>  drivers/gpu/drm/i915/intel_drv.h     |  2 ++
>  drivers/gpu/drm/i915/intel_pm.c      | 35 +++++++++++++++++++++++++++++++++++
>  3 files changed, 45 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 94c09bf0047d..1846fb510ebb 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -10195,6 +10195,7 @@ void intel_check_page_flip(struct drm_device *dev, int pipe)
>  	struct drm_i915_private *dev_priv = dev->dev_private;
>  	struct drm_crtc *crtc = dev_priv->pipe_to_crtc_mapping[pipe];
>  	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
> +	struct intel_unpin_work *work;
>  
>  	WARN_ON(!in_interrupt());
>  
> @@ -10202,12 +10203,16 @@ void intel_check_page_flip(struct drm_device *dev, int pipe)
>  		return;
>  
>  	spin_lock(&dev->event_lock);
> -	if (intel_crtc->unpin_work && __intel_pageflip_stall_check(dev, crtc)) {
> +	work = intel_crtc->unpin_work;
> +	if (work != NULL && __intel_pageflip_stall_check(dev, crtc)) {
>  		WARN_ONCE(1, "Kicking stuck page flip: queued at %d, now %d\n",
> -			 intel_crtc->unpin_work->flip_queued_vblank,
> -			 drm_vblank_count(dev, pipe));
> +			 work->flip_queued_vblank, drm_vblank_count(dev, pipe));
>  		page_flip_completed(intel_crtc);
> +		work = NULL;
>  	}
> +	if (work != NULL &&
> +	    drm_vblank_count(dev, pipe) - work->flip_queued_vblank > 1)
> +		intel_queue_rps_boost_for_request(dev, work->flip_queued_req);
>  	spin_unlock(&dev->event_lock);
>  }
>  
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index 0bcc5f36a810..4f1d02af1237 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -1263,6 +1263,8 @@ void gen6_rps_busy(struct drm_i915_private *dev_priv);
>  void gen6_rps_reset_ei(struct drm_i915_private *dev_priv);
>  void gen6_rps_idle(struct drm_i915_private *dev_priv);
>  void gen6_rps_boost(struct drm_i915_private *dev_priv);
> +void intel_queue_rps_boost_for_request(struct drm_device *dev,
> +				       struct drm_i915_gem_request *rq);
>  void ilk_wm_get_hw_state(struct drm_device *dev);
>  void skl_wm_get_hw_state(struct drm_device *dev);
>  void skl_ddb_get_hw_state(struct drm_i915_private *dev_priv,
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index 50c03472ea41..3e98f30517c6 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -6772,6 +6772,41 @@ int intel_freq_opcode(struct drm_i915_private *dev_priv, int val)
>  		return val / GT_FREQUENCY_MULTIPLIER;
>  }
>  
> +struct request_boost {
> +	struct work_struct work;
> +	struct drm_i915_gem_request *rq;
> +};
> +
> +static void __intel_rps_boost_work(struct work_struct *work)
> +{
> +	struct request_boost *boost = container_of(work, struct request_boost, work);
> +
> +	if (!i915_gem_request_completed(boost->rq, true))
> +		gen6_rps_boost(to_i915(boost->rq->ring->dev));
> +
> +	i915_gem_request_unreference__unlocked(boost->rq);
> +	kfree(boost);
> +}
> +
> +void intel_queue_rps_boost_for_request(struct drm_device *dev,
> +				       struct drm_i915_gem_request *rq)
> +{
> +	struct request_boost *boost;
> +
> +	if (rq == NULL || INTEL_INFO(dev)->gen < 6)
> +		return;
> +
> +	boost = kmalloc(sizeof(*boost), GFP_ATOMIC);
> +	if (boost == NULL)
> +		return;
> +
> +	i915_gem_request_reference(rq);
> +	boost->rq = rq;
> +
> +	INIT_WORK(&boost->work, __intel_rps_boost_work);
> +	queue_work(to_i915(dev)->wq, &boost->work);
> +}
> +
>  void intel_pm_setup(struct drm_device *dev)
>  {
>  	struct drm_i915_private *dev_priv = dev->dev_private;
> -- 
> 2.1.4
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch