[Bug 109408] [Kabylake] RPS waitboost regression since v4.20

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=109408

--- Comment #1 from Chris Wilson <chris at chris-wilson.co.uk> ---
One positive aspect here is that it seems both systems do employ the
"interactive" mode: that is a fixed set of EI thresholds biased to upclocking
the GPU. That is positive as it implies that the low frequencies may be more to
do with low EI busyness than anything else. The last tweak to waitboosting that
I recall was the very same interactive mode,

commit 027063b1606fea6df15c270e5f2a072d1dfa8fef [v4.19]
Author: Chris Wilson <chris at chris-wilson.co.uk>
Date:   Tue Jul 31 14:26:29 2018 +0100

    drm/i915: Interactive RPS mode

and before that

commit e9af4ea2b9e7e5d3caa6354be14de06b678ed0fa [v4.17]
Author: Chris Wilson <chris at chris-wilson.co.uk>
Date:   Thu Jan 18 13:16:09 2018 +0000

    drm/i915: Avoid waitboosting on the active request

So I think this may have been an accident. :)

Taking a wild guess:

commit 08e3e21a24d23db6a4adca90f7cb40d69e09d35c
Author: Lucas De Marchi <lucas.demarchi at intel.com>
Date:   Fri Aug 3 16:24:43 2018 -0700

    drm/i915: kill resource streamer support

(It's both new to v4.20 and had unexpected perf implications.)

-- 
You are receiving this mail because:
You are the QA Contact for the bug.
You are the assignee for the bug.
You are on the CC list for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/intel-gfx-bugs/attachments/20190121/be34d3e5/attachment.html>