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

[Tvrtko Ursulin]

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? ;(

Regards,

Tvrtko