[Intel-gfx] [PATCH] drm/i915: Optimistically spin for the request completion

[Chris Wilson]

On Tue, Mar 10, 2015 at 04:06:19PM +0000, Chris Wilson wrote:
> @@ -1235,12 +1257,20 @@ int __i915_wait_request(struct drm_i915_gem_request *req,
>  	if (ring->id == RCS && INTEL_INFO(dev)->gen >= 6)
>  		gen6_rps_boost(dev_priv, file_priv);
>  
> -	if (!irq_test_in_progress && WARN_ON(!ring->irq_get(ring)))
> -		return -ENODEV;
> -
>  	/* Record current time in case interrupted by signal, or wedged */
>  	trace_i915_gem_request_wait_begin(req);
>  	before = ktime_get_raw_ns();
> +
> +	/* Optimistic spin before touching IRQs */
Perhaps iff timeout == NULL, or pass it along and add a

if (timeout && timeout_after_eq(jiffies, timeout))
	break;

before the cpu_relax()?

> +	ret = __i915_spin_request(req);
> +	if (ret == 0)
> +		goto out;

-- 
Chris Wilson, Intel Open Source Technology Centre