Re: [PATCH v9 15/15] drm/i915: Add deadline based boost support

Rodrigo Vivi
2023-03-03T03:21:28Z

On Thu, Mar 02, 2023 at 03:53:37PM -0800, Rob Clark wrote:
> From: Rob Clark <robdclark@chromium.org>
>

missing some wording here...

> v2: rebase
>
> Signed-off-by: Rob Clark <robdclark@chromium.org>
> ---
> drivers/gpu/drm/i915/i915_request.c | 20 ++++++++++++++++++++
> 1 file changed, 20 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
> index 7503dcb9043b..44491e7e214c 100644
> --- a/drivers/gpu/drm/i915/i915_request.c
> +++ b/drivers/gpu/drm/i915/i915_request.c
> @@ -97,6 +97,25 @@ static bool i915_fence_enable_signaling(struct dma_fence *fence)
> return i915_request_enable_breadcrumb(to_request(fence));
> }
>
> +static void i915_fence_set_deadline(struct dma_fence *fence, ktime_t deadline)
> +{
> + struct i915_request *rq = to_request(fence);
> +
> + if (i915_request_completed(rq))
> + return;
> +
> + if (i915_request_started(rq))
> + return;

why do we skip the boost if already started?
don't we want to boost the freq anyway?

> +
> + /*
> + * TODO something more clever for deadlines that are in the
> + * future. I think probably track the nearest deadline in
> + * rq->timeline and set timer to trigger boost accordingly?
> + */

I'm afraid it will be very hard to find some heuristics of what's
late enough for the boost no?
I mean, how early to boost the freq on an upcoming deadline for the
timer?

> +
> + intel_rps_boost(rq);
> +}
> +
> static signed long i915_fence_wait(struct dma_fence *fence,
> bool interruptible,
> signed long timeout)
> @@ -182,6 +201,7 @@ const struct dma_fence_ops i915_fence_ops = {
> .signaled = i915_fence_signaled,
> .wait = i915_fence_wait,
> .release = i915_fence_release,
> + .set_deadline = i915_fence_set_deadline,
> };
>
> static void irq_execute_cb(struct irq_work *wrk)
> --
> 2.39.1
>