Re: [PATCH] drm/i915: Aggressively downclock Baytrail

[Jesse Barnes <jbarnes@virtuousgeek.org>]

On Thu,  3 Jul 2014 15:29:26 +0100
Chris Wilson <chris@chris-wilson.co.uk> wrote:

> Baytrail uses the RPS wait-boosting mechanism of Sandybridge+ but also has
> a very lax downclocking strategy (upclock if more than 90% busy over 76ms,
> downclock if less than 70% busy over 450ms). This causes Baytrail to use
> maximum clocks, and for them to stay high, when doing simple tasks such as
> scrolling through webpages. However, we can take a leaf out of the same
> wait-boost mechansim and apply the aggressive downclocking strategy from
> Sandybridge+ as well.
> 
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> ---

We really need a thorough test suite to cover stuff like this, mapping
frequency, power, and total energy over a big set of workloads to make
sure we're not adding big regressions.

I know you have the cairo traces, but did you also try this with a GL
benchmark suite?

I'm like the change (well you did mix in a cleanup to
set_rps_thresholds), I just want us to get better at collecting numbers
for this stuff...

-- 
Jesse Barnes, Intel Open Source Technology Center