[Intel-gfx] [PATCH v2] drm/i915: Priority boost for new clients

[Tvrtko Ursulin]

On 07/08/2018 16:02, Chris Wilson wrote:
> Quoting Tvrtko Ursulin (2018-08-07 10:08:28)
>>
>> On 07/08/2018 08:29, Chris Wilson wrote:
>>> +     /*
>>> +      * The active request is now effectively the start of a new client
>>> +      * stream, so give it the equivalent small priority bump to prevent
>>> +      * it being gazumped a second time by another peer.
>>> +      */
>>> +     if (!(prio & I915_PRIORITY_NEWCLIENT)) {
>>> +             list_move_tail(&active->sched.link,
>>> +                            lookup_priolist(engine,
>>> +                                            prio | I915_PRIORITY_NEWCLIENT));
>>>        }
>>>    }
>>>    
>>>
>>
>> This sounds fair, I think I'm okay with it. Does it still work well for
>> mixed media workloads?
> 
> Grr. Current drm-tip is scoring much much higher in fairness than I
> remember, and there's no apparent improvement, even little room for
> possible improvement. When in doubt, blame ksoftirqd ;)

Perhaps previous testing was before direct submission?

> Quite surprising though, it was (at least if memory serves) a dramatic
> improvement from this patch. Time to see if the metrics do resemble what
> I think they should be, and to see if I can find a good example in
> media-bench.pl

I should maybe rename it to wsim-bench.pl with a switch to select 
workload groups per directory or something..

Regards,

Tvrtko