Re: [PATCH 47/55] drm/i915: Disable waitboosting for a saturated engine

Joonas Lahtinen
2016-07-26T12:40:31Z

On ma, 2016-07-25 at 18:32 +0100, Chris Wilson wrote:
> If the user floods the GPU with so many requests that the engine stalls
> waiting for free space, don't automatically promote the GPU to maximum
> frequencies. If the GPU really is saturated with work, it will migrate
> to high clocks by itself, otherwise it is merely a user flooding us with
> busy-work.
>

Should this even come with Fixes: ?

Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> ---
>  drivers/gpu/drm/i915/intel_ringbuffer.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
> index 507576ef8077..90e46d1b04e2 100644
> --- a/drivers/gpu/drm/i915/intel_ringbuffer.c
> +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
> @@ -2314,7 +2314,7 @@ static int wait_for_space(struct drm_i915_gem_request *req, int bytes)
>   if (WARN_ON(&target->ring_link == &ring->request_list))
>   return -ENOSPC;
>
> - ret = __i915_wait_request(target, true, NULL, NULL);
> + ret = __i915_wait_request(target, true, NULL, NO_WAITBOOST);
>   if (ret)
>   return ret;
>
--
Joonas Lahtinen
Open Source Technology Center
Intel Corporation