[Intel-gfx] [PATCH 0/3] RFC: force throttling/fairness

[Chris Wilson]

On Fri, 28 Oct 2011 22:55:26 -0700, Ben Widawsky <ben at bwidawsk.net> wrote:
> These patches are pretty raw as I'm hoping to get some comments before
> working to hard too clean them up. The goal is GPU fairness for clients
> running on i915.

The biggest danger I see is that num_outstanding is only decremented
in retire_requests, which under the right circumstances (a single hog or
a plurarity) will cause latencies of over 1s. Also this unnecessarily
penalises benchmarks, i.e. a single active client.

To start the bikeshedding, we need a debugfs to show the current clients
and their scheduling data.

I would like to see the hog values moved at least into the file_priv and
a gpuprio ioctl so that we can start prioritising by file. It would then
be possible for a compositing render server to open a fd for it owns
high priority composition and a fd per client and individual tune their
priorities. And before you know what's hit you someone will request
cgroups...

It would probably be best to overengineer the ioctl interface as a
facsimile of the more recent cpu schedulers.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre