Re: [Intel-gfx] [PATCH v3] drm/i915/execlists: Set queue priority from secondary port
Quoting Tvrtko Ursulin (2018-04-11 13:03:00)
>
> On 11/04/2018 12:34, Chris Wilson wrote:
> > Quoting Chris Wilson (2018-04-11 11:39:29)
> >> We can refine our current execlists->queue_priority if we inspect
> >> ELSP[1] rather than the head of the unsubmitted queue. Currently, we use
> >> the unsubmitted queue and say that if a subsequent request is more
> >> important than the current queue, we will rerun the submission tasklet
> >> to evaluate the need for preemption. However, we only want to preempt if
> >> we need to jump ahead of a currently executing request in ELSP. The
> >> second reason for running the submission tasklet is amalgamate requests
> >> into the active context on ELSP[0] to avoid a stall when ELSP[0] drains.
> >> (Though repeatedly amalgamating requests into the active context and
> >> triggering many lite-restore is off question gain, the goal really is to
> >> put a context into ELSP[1] to cover the interrupt.) So if instead of
> >> looking at the head of the queue, we look at the context in ELSP[1] we
> >> can answer both of the questions more accurately -- we don't need to
> >> rerun the submission tasklet unless our new request is important enough
> >> to feed into, at least, ELSP[1].
> >>
> >> v2: Add some comments from the discussion with Tvrtko.
> >> v3: More commentary to cross-reference queue_request()
> >>
> >> References: f6322eddaff7 ("drm/i915/preemption: Allow preemption between
> >> submission ports")
> >> Signed-off-by: Chris Wilson
> >> Cc: Michał Winiarski
> >> Cc: Michel Thierry
> >> Cc: Mika Kuoppala
> >> Cc: Tvrtko Ursulin
> >
> > From the discussion thread,
> >
> > Reviewed-by: Tvrtko Ursulin
> >
> > I assume Tvrtko is happy with the comments added based on that
> > conversation.
>
> Yes, all fine!
Forgot to say, thanks and pushed.
If you are feeling better, there's the igt that purports to hit the issue
as well: https://patchwork.freedesktop.org/series/41535/
Or one of the Ms!
-Chris
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Re: [Intel-gfx] [PATCH v3] drm/i915/execlists: Set queue priority from secondary port
On 11/04/2018 12:34, Chris Wilson wrote:
Quoting Chris Wilson (2018-04-11 11:39:29)
We can refine our current execlists->queue_priority if we inspect
ELSP[1] rather than the head of the unsubmitted queue. Currently, we use
the unsubmitted queue and say that if a subsequent request is more
important than the current queue, we will rerun the submission tasklet
to evaluate the need for preemption. However, we only want to preempt if
we need to jump ahead of a currently executing request in ELSP. The
second reason for running the submission tasklet is amalgamate requests
into the active context on ELSP[0] to avoid a stall when ELSP[0] drains.
(Though repeatedly amalgamating requests into the active context and
triggering many lite-restore is off question gain, the goal really is to
put a context into ELSP[1] to cover the interrupt.) So if instead of
looking at the head of the queue, we look at the context in ELSP[1] we
can answer both of the questions more accurately -- we don't need to
rerun the submission tasklet unless our new request is important enough
to feed into, at least, ELSP[1].
v2: Add some comments from the discussion with Tvrtko.
v3: More commentary to cross-reference queue_request()
References: f6322eddaff7 ("drm/i915/preemption: Allow preemption between submission
ports")
Signed-off-by: Chris Wilson
Cc: Michał Winiarski
Cc: Michel Thierry
Cc: Mika Kuoppala
Cc: Tvrtko Ursulin
From the discussion thread,
Reviewed-by: Tvrtko Ursulin
I assume Tvrtko is happy with the comments added based on that
conversation.
Yes, all fine!
Regards,
Tvrtko
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Re: [Intel-gfx] [PATCH v3] drm/i915/execlists: Set queue priority from secondary port
Quoting Chris Wilson (2018-04-11 11:39:29)
> We can refine our current execlists->queue_priority if we inspect
> ELSP[1] rather than the head of the unsubmitted queue. Currently, we use
> the unsubmitted queue and say that if a subsequent request is more
> important than the current queue, we will rerun the submission tasklet
> to evaluate the need for preemption. However, we only want to preempt if
> we need to jump ahead of a currently executing request in ELSP. The
> second reason for running the submission tasklet is amalgamate requests
> into the active context on ELSP[0] to avoid a stall when ELSP[0] drains.
> (Though repeatedly amalgamating requests into the active context and
> triggering many lite-restore is off question gain, the goal really is to
> put a context into ELSP[1] to cover the interrupt.) So if instead of
> looking at the head of the queue, we look at the context in ELSP[1] we
> can answer both of the questions more accurately -- we don't need to
> rerun the submission tasklet unless our new request is important enough
> to feed into, at least, ELSP[1].
>
> v2: Add some comments from the discussion with Tvrtko.
> v3: More commentary to cross-reference queue_request()
>
> References: f6322eddaff7 ("drm/i915/preemption: Allow preemption between
> submission ports")
> Signed-off-by: Chris Wilson
> Cc: Michał Winiarski
> Cc: Michel Thierry
> Cc: Mika Kuoppala
> Cc: Tvrtko Ursulin
From the discussion thread,
Reviewed-by: Tvrtko Ursulin
I assume Tvrtko is happy with the comments added based on that
conversation.
-Chris
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