Re: [PATCH] drm/i915: Restrict GPU boost to the RCS engine

[Chris Wilson <chris@chris-wilson.co.uk>]

On Wed, Jul 09, 2014 at 10:09:00AM +0530, Deepak S wrote:
> 
> On Monday 07 July 2014 02:35 PM, Daniel Vetter wrote:
> >On Tue, Jun 24, 2014 at 05:22:17PM +0530, Deepak S wrote:
> >>Hi Chris/Daniel,
> >>
> >>The patch is  helping in some of the side-effects due to gpu boost. I
> >>still need to get more data. I will keep the thread updated.
> >Ping. Might as well review it, too.
> >-Daniel
> >
> >>Thanks
> >>Deepak
> >>
> >>On Thursday 12 June 2014 03:02 PM, Daniel Vetter wrote:
> >>>Adding Deepak for testing, this hopefully alleviates the bad
> >>>side-effects of the gpu booster he's seeing.
> >>>-Daniel
> >>>
> >>>On Thu, Jun 12, 2014 at 11:28 AM, Chris Wilson <chris@chris-wilson.co.uk> wrote:
> >>>>Make the assumption that media workloads are not as latency sensitive
> >>>>for __wait_seqno, and that upclocking the GPU does not affect the BLT
> >>>>engine. Under that assumption, we only wait to forcibly upclock the GPU
> >>>>when we are stalling for results from the render pipeline.
> >>>>
> >>>>Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> >>>>---
> >>>>  drivers/gpu/drm/i915/i915_gem.c | 2 +-
> >>>>  1 file changed, 1 insertion(+), 1 deletion(-)
> >>>>
> >>>>diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> >>>>index 5951618a6b08..242b595a0403 100644
> >>>>--- a/drivers/gpu/drm/i915/i915_gem.c
> >>>>+++ b/drivers/gpu/drm/i915/i915_gem.c
> >>>>@@ -1409,7 +1409,7 @@ static int __wait_seqno(struct intel_engine_cs *ring, u32 seqno,
> >>>>
> >>>>         timeout_expire = timeout ? jiffies + timespec_to_jiffies_timeout(timeout) : 0;
> >>>>
> >>>>-       if (INTEL_INFO(dev)->gen >= 6 && can_wait_boost(file_priv)) {
> >>>>+       if (INTEL_INFO(dev)->gen >= 6 && ring->id == RCS && can_wait_boost(file_priv)) {
> >>>>                 gen6_rps_boost(dev_priv);
> >>>>                 if (file_priv)
> >>>>                         mod_delayed_work(dev_priv->wq,
> >>>>--
> >>>>2.0.0
> >>>>
> >>>>_______________________________________________
> >>>>Intel-gfx mailing list
> >>>>Intel-gfx@lists.freedesktop.org
> >>>>http://lists.freedesktop.org/mailman/listinfo/intel-gfx
> >>>
> Sorry for the delayed response. I am fine with this patch. This is helping us in some of the workload senarios.
> 
> Just one concern here. Since we are avoiding boost for Media related workload, we might end up running GPU at RPn. Which might impact media workload.
> I think we need another patch to run GPU at RPe if the boost is not enabled for media.

That should already be taken care of by the normal upclocking logic.
Except that byt is still using those original ineffectual values for
reclocking....
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre