[Intel-gfx] [PATCH v3] drm/i915/bdw: BDW Software Turbo

[Chris Wilson]

On Wed, Aug 27, 2014 at 08:57:56PM +0200, Daniel Vetter wrote:
> On Thu, Aug 14, 2014 at 12:37:53PM -0700, Jesse Barnes wrote:
> > On Mon, 11 Aug 2014 23:33:57 +0200
> > Daniel Vetter <daniel at ffwll.ch> wrote:
> > 
> > > On Mon, Aug 11, 2014 at 11:08:38AM -0700, Daisy Sun wrote:
> > > > BDW supports GT C0 residency reporting in constant time unit. Driver
> > > > calculates GT utilization based on C0 residency and adjusts RP
> > > > frequency up/down accordingly. For offscreen workload specificly,
> > > > set frequency to RP0.
> > > > 
> > > > Offscreen task is not restricted by frame rate, it can be
> > > > executed as soon as possible. Transcoding and serilized workload
> > > > between CPU and GPU both need high GT performance, RP0 is a good
> > > > option in this case. RC6 will kick in to compensate power
> > > > consumption when GT is not active.
> > > > 
> > > > v2: Rebase on recent drm-intel-nightly
> > > > v3: Add flip timerout monitor, when no flip is deteced within
> > > > 100ms, set frequency to RP0.
> > > 
> > > Ok, let's make this really clear:
> > > 
> > > If you wire this into the flip handling in any way, I will not merge your
> > > patch. The timer should be fully independant and tie into the gpu
> > > busy/idle handling we already have.
> > 
> > Sounds like Daisy won't be able to spend any more time on this either.
> > 
> > So we're left with this patch, which does improve things for most
> > cases, or no patch, which leaves things universally bad.
> > 
> > Unless someone wants to pick up the additional work and testing of
> > using a timer scheme, making sure we don't have needless wakeups, and
> > generally improve power/perf across even more cases than this patch.
> 
> I'm taking this as an ack from you and pulled the patch into dinq.

Maybe also a nak from me for the bad design and poor integration with
the existing RPS infrastructue?
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre