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

[Jesse Barnes <jbarnes@virtuousgeek.org>]

On Fri, 28 Jun 2013 12:10:51 -0700
Arjan van de Ven <arjan@linux.intel.com> wrote:

> On 6/28/2013 11:37 AM, Chris Wilson 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.
> > -Chris
> >
> 
> Is there a way to force the GPU always to run at the top speed?
> (since it might well be the most efficient way to run things due to race-to-halt)

Yeah I posted a patch for that earlier; adds a new i915.enable_turbo
param.  If disabled, it just always runs at top speed when not in C6.

-- 
Jesse Barnes, Intel Open Source Technology Center