Bug 93394 - [BDW, BSW] GLbenchmark_V3.0_gl_driver/gl_driver_offscreen/Synmark2_v6_Batch6/Batch7 show performance dropped by 5%-12%
Summary: [BDW, BSW] GLbenchmark_V3.0_gl_driver/gl_driver_offscreen/Synmark2_v6_Batch6/...
Status: RESOLVED WONTFIX
Alias: None
Product: Mesa
Classification: Unclassified
Component: Drivers/DRI/i965 (show other bugs)
Version: unspecified
Hardware: Other All
: medium normal
Assignee: Kenneth Graunke
QA Contact: Intel 3D Bugs Mailing List
URL:
Whiteboard:
Keywords: bisected
Depends on:
Blocks:
 
Reported: 2015-12-16 08:21 UTC by wendy.wang
Modified: 2016-11-02 07:04 UTC (History)
1 user (show)

See Also:
i915 platform:
i915 features:

Attachments
xorg.log (18.36 KB, text/plain)
2015-12-16 08:21 UTC, wendy.wang 		Details
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Description wendy.wang 2015-12-16 08:21:05 UTC 
Created attachment 120536 [details]
xorg.log

Test environment:
Failed platforms: BDW/BSW

Mesa Regression: Yes, bisect is under progress

Bad gfx sw stack info:
Mesa: git-7752bbc
Kernel: 4.4-rc4-drm-intel-nightly_ad271e_20151213+
xf83: 2.99.917-517-g6c4ffba
xserver: 1.18.99.1

GLbenchmark_V3.0_gl_driver/gl_driver_offscreen/Synmark2_v6_Batch6/Batch7 show performance dropped by 5%-12%

Reproduce steps:
1. cd /gfxbench3_desktop/build/linux/gfxbench_Release/mainapp
2. export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/games/OpenGL/gfxbench3_desktop/install/linux/lib
3. ./mainapp vblank_mode=0 -t gl_alu -fullscreen 1 -w 1920 -h 1080

xorg file has been attached.
Comment 1 ye.tian 2015-12-18 06:59:39 UTC 
It's mesa regression.By bisect, shows the first bad mesa commit is c59d1b1.

commit c59d1b1fd1ac5dca3b769f42fe0e42a11c10d4b8
Author:     Kenneth Graunke <kenneth@whitecape.org>
AuthorDate: Fri Oct 9 17:07:23 2015 -0700
Commit:     Kenneth Graunke <kenneth@whitecape.org>
CommitDate: Fri Dec 11 13:11:15 2015 -0800

    i965: Add tessellation shader sampler support.

    Based on code by Chris Forbes and Fabian Bieler.

    Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
    Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Comment 2 Matt Turner 2016-11-02 05:11:35 UTC 
I suspect the commit just caused the benchmark to do more work. Ken, is there anything to do here?
Comment 3 Kenneth Graunke 2016-11-02 07:04:25 UTC 
The benchmark should do the same thing, but adding additional tracked state atoms increased the draw call overhead.  And these are CPU overhead benchmarks.

I don't think it's worth tracking as a regression.  We can't exactly retract core features.  We just need to optimize away draw call CPU overhead.

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