[PATCH 3/3] drm/i915/gt: Improve "race-to-idle" at low frequencies

[Vivi, Rodrigo]

On Tue, 2021-11-23 at 09:17 +0000, Tvrtko Ursulin wrote:
> 
> On 22/11/2021 18:44, Rodrigo Vivi wrote:
> > On Wed, Nov 17, 2021 at 02:49:55PM -0800, Vinay Belgaumkar wrote:
> > > From: Chris Wilson <chris at chris-wilson.co.uk>
> > > 
> > > While the power consumption is proportional to the frequency,
> > > there is
> > > also a static draw for active gates. The longer we are able to
> > > powergate
> > > (rc6), the lower the static draw. Thus there is a sweetspot in
> > > the
> > > frequency/power curve where we run at higher frequency in order
> > > to sleep
> > > longer, aka race-to-idle. This is more evident at lower
> > > frequencies, so
> > > let's look to bump the frequency if we think we will benefit by
> > > sleeping
> > > longer at the higher frequency and so conserving power.
> > > 
> > > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> > > Cc: Vinay Belgaumkar <vinay.belgaumkar at intel.com>
> > > Cc: Tvrtko Ursulin <tvrtko.ursulin at linux.intel.com>
> > 
> > Please let's not increase the complexity here, unless we have a
> > very good
> > and documented reason.
> > 
> > Before trying to implement anything smart like this in the driver
> > I'd like
> > to see data, power and performance results in different platforms
> > and with
> > different workloads.
> 
> Who has such test suite and test farm which isn't focused to
> workloads 
> from a single customer? ;(

Okay, maybe we don't need to cover the world here. But without seen any
data at all it is hard to make this call.

> 
> Regards,
> 
> Tvrtko