[Intel-gfx] [PATCH v2 3/6] drm/i915/guc: use a separate GuC client for each engine

[Chris Wilson]

On Thu, Jul 21, 2016 at 07:15:39PM +0100, Dave Gordon wrote:
> When using a single GuC client for multiple engines, the i915 driver has
> to merge all work items into a single work queue, which the GuC firmware
> then demultiplexes into separate submission queues per engine. In
> theory, this could lead to the single queue becoming a bottleneck in
> which an excess of outstanding work for one or more engines might
> prevent work for an idle engine reaching the hardware.
> 
> To reduce this risk, we can create one GuC client per engine. Each will
> have its own workqueue, to be used only for work targeting a single
> engine, so there will be no cross-engine contention for workqueue slots.
> 
> Signed-off-by: Dave Gordon <david.s.gordon at intel.com>
> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>

Does guc_context_desc.engines_used have any effect?
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre