Re: [PATCH] drm/i915: boost GPU and CPU freq when leaving idle

[Jesse Barnes <jbarnes@virtuousgeek.org>]

On Fri, 28 Jun 2013 19:37:01 +0100
Chris Wilson <chris@chris-wilson.co.uk> wrote:

> On Fri, Jun 28, 2013 at 09:54:32AM -0700, Jesse Barnes wrote:
> > Coming out of idle is usually due to some sort of user input (swiping a
> > screen, clicking a button) and often results in some sort of graphical
> > animation.  To prevent stutter for a CPU or GPU intensive animation,
> > boost the GPU and CPU freq to the maximum to get the first frame out as
> > quickly as possible.  The normal CPU and GPU frequency management code
> > will take over from there and (hopefully) clock down to save power as
> > needed if the max frequencies aren't required.
> > 
> > This could probably be done more cleanly, and possibly without another
> > uncached read in the execbuf path if we tracked idleness elsewhere.  I'm
> > also unsure about the cpufreq calls; I don't really know if this will do
> > what I want...
> 
> Would seem like a good idea to make intel_mark_busy() dtrt and use them.

That'll give us a slightly delayed idle indicator, but it should work
ok...

Owen, if this patch looks like it'll work for you, I'll update it to use
our mark busy/idle stuff and see if we can merge it upstream.

Thanks,
-- 
Jesse Barnes, Intel Open Source Technology Center