[Intel-gfx] [PATCH] drm/i915: Increase the RC6p threshold.

[Zhang, Ouping]

Increase the RC6p threshold from 100000 to 150000, there is no power difference between the two values.
for example:
(1) I915_WRITE(GEN6_RC6p_THRESHOLD, 100000);
video time: 11'
video avg watt 31.3
watt-hour: 5.6

(2) I915_WRITE(GEN6_RC6p_THRESHOLD, 150000);
video time: 11'
video avg watt 31.2
watt-hour: 5.6

-----Original Message-----
From: Jesse Barnes [mailto:jbarnes at virtuousgeek.org] 
Sent: Tuesday, February 26, 2013 12:14 AM
To: Zhang, Ouping
Cc: Stéphane Marchesin; intel-gfx at lists.freedesktop.org
Subject: Re: [Intel-gfx] [PATCH] drm/i915: Increase the RC6p threshold.

How does the watt-hour result compare to before the patch?

Thanks,
Jesse

On Mon, 25 Feb 2013 07:33:38 +0000
"Zhang, Ouping" <ouping.zhang at intel.com> wrote:

> running video workload, video avg watt = 38.4 and watt-hour = 6.9 cat 
> /sys/class/drm/card0/power/rc6_residency_ms
> cat /sys/class/drm/card0/power/rc6p_residency_ms
> rc6_residency_ms increase from 6708 to 483627 rc6p_residency_ms 
> increase from 410092 to 423378
> 
> -----Original Message-----
> From: Jesse Barnes [mailto:jbarnes at virtuousgeek.org]
> Sent: Friday, February 22, 2013 12:50 AM
> To: Zhang, Ouping
> Cc: Stéphane Marchesin; intel-gfx at lists.freedesktop.org
> Subject: Re: [Intel-gfx] [PATCH] drm/i915: Increase the RC6p threshold.
> 
> You have to modify the kernel to make the change Stephane suggested, then measure the energy consumption across your workloads.  I'd expect the residency to change, but I'm ultimately concerned with the energy used.
> 
> Jesse
> 
> On Thu, 21 Feb 2013 05:08:10 +0000
> "Zhang, Ouping" <ouping.zhang at intel.com> wrote:
> 
> > Hi Jesse,
> > 
> > Do you mean increase /sys/class/drm/card0/power/rc6p_residency_ms from 100000 to 150000, and measure power difference on IVB when system is on idle?
> > 
> > -----Original Message-----
> > From: Jesse Barnes [mailto:jbarnes at virtuousgeek.org]
> > Sent: Wednesday, February 20, 2013 8:16 AM
> > To: Stéphane Marchesin
> > Cc: intel-gfx at lists.freedesktop.org; Zhang, Ouping
> > Subject: Re: [Intel-gfx] [PATCH] drm/i915: Increase the RC6p threshold.
> > 
> > On Tue, 19 Feb 2013 15:53:56 -0800
> > Stéphane Marchesin <marcheu at chromium.org> wrote:
> > 
> > > On Tue, Jan 29, 2013 at 7:41 PM, Stéphane Marchesin <marcheu at chromium.org>wrote:
> > > 
> > > > This increases GEN6_RC6p_THRESHOLD from 100000 to 150000. For 
> > > > some reason this avoids the gen6_gt_check_fifodbg.isra warnings 
> > > > and associated GPU lockups, which makes my ivy bridge machine stable.
> > > >
> > > >
> > > Ping?
> > 
> > Seems ok to me.  Ouping, can you measure any power difference between the two values?
> > 
> > Thanks,
> > --
> > Jesse Barnes, Intel Open Source Technology Center
> 
> 
> --
> Jesse Barnes, Intel Open Source Technology Center


--
Jesse Barnes, Intel Open Source Technology Center