[Mesa-dev] i965: disable_throttling

[Marathe, Yogesh]

Hi,

> -----Original Message-----
> Hi,
> 
> On 09.06.2017 09:21, Marathe, Yogesh wrote:
> > I’m looking forward to set this brw->disable_throttling to true, I’m
> > actually observing adverse effect on performance benchmarks after I
> > force set that to true. What’s the expectation from disable_throttling
> > here?
> 
> By default Mesa throttles its buffer swaps so that compositor is able to easier
> insert its own batches to better place in GPU batch queue.
> 
> If throttling is disabled, compositor needs to discard more frames as obsolete,
> because benchmark is running too many frames forward of it.
> 
> Normally having no throttling means that:
> * composited performance looks worse to the user, because only some of the
> rendered frames end up on screen
> * benchmark runs faster because compositor composes less frames, i.e.
> takes less of the system bandwidth
> 

Thanks Eero. Essentially, you are saying having disable_trottling=true is
actually _not_ beneficial from compositor's perspective where GPU is not
matching speeds with that of benchmark. I will leave it to default then. 

> 
>  > BTW, this is on android.
> 
> On TDP constrained machines, power management can do funky things.  When
> in doubt, use fixed GPU & CPU speeds are re-test.
> 

Alright.

> 
> 
> 	- Eero
> 
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