Bug 66297

Summary: [IVB/HSW bisected] cairo-trace/(benchmark)swfdec-youtube.trace reduced by ~20%
Product: xorg Reporter: meng <mengmeng.meng>
Component: Driver/intelAssignee: Chris Wilson <chris>
Status: VERIFIED FIXED QA Contact: Intel GFX Bugs mailing list <intel-gfx-bugs>
Severity: major    
Priority: medium    
Version: unspecified   
Hardware: All   
OS: Linux (All)   
Whiteboard:
i915 platform: i915 features:

Description meng 2013-06-28 06:30:07 UTC 
System Environment:       
----------------------------------------------
Platform:  HSW/IVB
Mesa:		(master)6aabd9490c7b71d363a384935597b3e37295e61e
Xf86_video_intel:	(master)2.21.9-51-g62e42de300275a668a326357d454062221714fe8
Cairo:		(master)4d9439132de85c0f0f4d5b5a474ea7164910251e
Kernel:	(drm-intel-nightly) 51c5e63195eff27962be315b5c835cdc2fe034fb

Bug detailed description:
----------------------------------------------
cairo-trace/(benchmark)swfdec-youtube.trace reduced by ~20% on IVB/HSW.
It’s Xf86_video_intel regression, bisecting show the first bad commit is that:

commit 48028a7c923fa0d66b01e8e94d4f0742866f78ec
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Fri Jun 21 14:29:43 2013 +0100
    sna: Inspect availablity of render before prefering to use the GPU
    Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

Performance on IVB
---------------------------------------
                      git-48028a7         git-71fc834
swfdec-youtube.trace     0.385               0.30
  

Reproduce steps:
---------------------------------------------
1. xinit&
2.vblank_mode=0 CAIRO_TEST_TARGET=xlib ./cairo-perf-trace -i 12 /home/cairo-traces/benchmark/swfdec-youtube.trace
Comment 1 Chris Wilson 2013-06-28 07:57:44 UTC 
Confirmed; looks to be a bit of a puzzler.
Comment 2 Chris Wilson 2013-06-28 10:27:20 UTC 
commit e979d32bb71fef7341ceb9c2b2e80c6dfa50a7b3
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Fri Jun 28 10:59:23 2013 +0100

    sna/gen2+: Consider precision in render operation placement
    
    Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=66297
    Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Comment 3 meng 2013-07-01 00:50:10 UTC 
Verified it.

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