[Intel-gfx] [PATCH 2/5] drm/i915/perf: allow holding preemption on filtered ctx

[Lionel Landwerlin]

On 21/05/2019 17:36, Chris Wilson wrote:
> Quoting Lionel Landwerlin (2019-05-21 15:08:52)
>> diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
>> index f263a8374273..2ad95977f7a8 100644
>> --- a/drivers/gpu/drm/i915/gt/intel_lrc.c
>> +++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
>> @@ -2085,7 +2085,7 @@ static int gen9_emit_bb_start(struct i915_request *rq,
>>          if (IS_ERR(cs))
>>                  return PTR_ERR(cs);
>>   
>> -       *cs++ = MI_ARB_ON_OFF | MI_ARB_ENABLE;
>> +       *cs++ = MI_ARB_ON_OFF | rq->hw_context->arb_enable;
> My prediction is that this will result in this context being reset due 
> to preemption timeouts and the context under profile being banned. 
> Note that preemption timeouts will be the primary means for hang 
> detection for endless batches. -Chris

Thanks,

One question : how is that dealt with with compute workloads at the moment?
I though those where still not fully preemptable.

I need to rework this with a more "software" approach holding on preemption.
Adding a condition in intel_lrc.c need_preempt() looks like the right 
direction?

Cheers,

-Lionel