Re: [PATCH v2] drm/i915/bdw: BDW Software Turbo

Sun, Daisy
2014-07-10T18:43:34Z

GT is not going to run at a single frequency all the time actually. It
starts from a single frequency, and then will dynamically adjust
according to the GT utilization, either go up or down.
From this perspective, SW turbo function the same as the HW turbo.

For the algorithm, we did go over the design forum before implementation.
What kind of improvement is expected? Please let me know if any
important case is not taken into account. Thanks.

- Daisy
On 7/10/2014 1:32 AM, Chris Wilson wrote:
> On Wed, Jul 09, 2014 at 06:00:48PM -0700, Daisy Sun wrote:
>> BDW supports GT C0 residency reporting in constant time unit. Driver calculates
>> GT utilization based on C0 residency and adjusts RP frequency up/down
>> accordingly.
> This explanation is a bit thin on the ground for why you want to run
> permanently at a single GPU frequency. And the algorithm looks primitive
> at best.
> -Chris
>