Re: [PATCH] drm/i915: Use PM QoS to prevent C-state memory starvation of the GPU

Chris Wilson
2011-01-15T11:13:39Z

On Sat, 15 Jan 2011 11:34:31 +0100, Paolo Ornati <ornati@gmail.com> wrote:
> On Wed, 8 Dec 2010 16:24:35 +0000
> Chris Wilson <chris@chris-wilson.co.uk> wrote:
>
> > This is just a preliminary attempt to see if this even helps. Obviously
> > some more effort will need to be spent investigating a better choice of
> > latency and when we need to request it, but first: does this help?
>
> Sorry for the very long delay... it seems I've latency problems too ;)
>
> As for Andrew's comment it looks I need a recent kernel to actually
> test this patch:
>
> "Do you have the 2.6.36.2 candidate patch that fixes pm_qos in? From
> the description, it looks like pm_qos doesn't work at all without it."
>
> The "problem" is that I cannot reproduce it with 2.6.37 (tested
> yesterday for 8+ hours), but maybe it's just hidden by some coincidence.

Check with powertop to see if anything is preventing low C-states. It would
be great if it just magically fixed itself...
-Chris

--
Chris Wilson, Intel Open Source Technology Centre