Re: [PATCH v4 08/38] drm/i915: Prepare retire_requests to handle out-of-order seqnos

Chris Wilson
2016-01-11T22:10:36Z

On Mon, Jan 11, 2016 at 06:42:37PM +0000, John.C.Harrison@Intel.com wrote:
> From: John Harrison <John.C.Harrison@Intel.com>
>
> A major point of the GPU scheduler is that it re-orders batch buffers
> after they have been submitted to the driver. This leads to requests
> completing out of order. In turn, this means that the retire
> processing can no longer assume that all completed entries are at the
> front of the list. Rather than attempting to re-order the request list
> on a regular basis, it is better to simply scan the entire list.

This is a major misstep. Just think in terms of per-context timelines,
and retirment order within those timelines being consistent..
-Chris

--
Chris Wilson, Intel Open Source Technology Centre