[Intel-gfx] [PATCH] drm/i915: Restrict GPU boost to the RCS engine

[Chris Wilson]

On Wed, Dec 17, 2014 at 06:02:06PM +0100, Daniel Vetter wrote:
> On Wed, Dec 17, 2014 at 03:12:05PM +0000, Chris Wilson wrote:
> > On Thu, Jun 12, 2014 at 10:28:55AM +0100, Chris Wilson wrote:
> > > Make the assumption that media workloads are not as latency sensitive
> > > for __wait_seqno, and that upclocking the GPU does not affect the BLT
> > > engine. Under that assumption, we only wait to forcibly upclock the GPU
> > > when we are stalling for results from the render pipeline.
> > 
> > For reference, the BLT does depend upon the gpu frequency (and acts as
> > a media source of busyness), and to lesser extent the ring/memory bw,
> > also controlled as a side-effect of gpu frequency.
> > 
> > Tested on ivb, i7-3720QM
> 
> Since the patch landed already, can you please submit a fixup to add the
> || ring == BLT with Deepak on cc so he can review it?

I am not overly concerned as I don't have a pure BLT benchmark that
isn't quickly ramped to maximum by the more responsive RPS tuning we
have in IVB/HSW (and patches exist for VLV). I also prefer the concept
of detecting dropped frames for boosting, irrespective of waits. That is
the best I have for making gnome-shell snappy.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre