[Intel-gfx] [PATCH] drm/i915: Execlists small cleanups and micro-optimisations

[Chris Wilson]

On Fri, Feb 26, 2016 at 03:37:35PM +0000, Tvrtko Ursulin wrote:
> -	if (ring->disable_lite_restore_wa) {
> -		/* Prevent a ctx to preempt itself */
> -		if ((status & GEN8_CTX_STATUS_ACTIVE_IDLE) &&
> -		    (submit_contexts != 0))
> -			execlists_context_unqueue(ring);
> -	} else if (submit_contexts != 0) {
> +	if (submit_contexts && (!ring->disable_lite_restore_wa ||
> +	    (ring->disable_lite_restore_wa && (status &
> +	    GEN8_CTX_STATUS_ACTIVE_IDLE))))

A little clumsy.

if (submit_contexts) {
	if (!ring->disable_lite_restore_wa == 0 ||
	    status & GEN8_CTX_STATUS_ACTIVE_IDLE)
		execlists_context_unqueue__locked(ring);
}

i.e. checking for ring->disable_lite_restore_wa != 0 is redundant (as it
must be true along the false branch of !ring->disable_lite_restore)

And if we take a moment to clean up the logic there

>  	list_add_tail(&request->execlist_link, &ring->execlist_queue);
> -	if (num_elements == 0)
> +	if (num_elements == 0) {
> +		spin_lock(&dev_priv->uncore.lock);
> +		intel_uncore_forcewake_get__locked(dev_priv, FORCEWAKE_ALL);
> +
>  		execlists_context_unqueue(ring);
>  
> -	spin_unlock_irq(&ring->execlist_lock);
> +		intel_uncore_forcewake_put__locked(dev_priv, FORCEWAKE_ALL);
> +		spin_unlock(&dev_priv->uncore.lock);
> +	}

should we hide the locks here with
void execlists_context_unqueue()
{
	spin_lock(&dev_priv->uncore.lock);
	intel_uncore_forcewake_get__locked(dev_priv, FORCEWAKE_ALL);

	execlists_context_unqueue__locked(ring);

	intel_uncore_forcewake_put__locked(dev_priv, FORCEWAKE_ALL);
	spin_unlock(&dev_priv->uncore.lock);

}
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre