Bug 86656 - glMark2 performance regression on mesa 10.3 or master branch
Summary: glMark2 performance regression on mesa 10.3 or master branch
Status: RESOLVED FIXED
Alias: None
Product: Mesa
Classification: Unclassified
Component: Drivers/DRI/i965 (show other bugs)
Version: git
Hardware: x86-64 (AMD64) All
: medium normal
Assignee: Kenneth Graunke
QA Contact: Intel 3D Bugs Mailing List
URL:
Whiteboard:
Keywords:
Depends on:
Blocks:
 
Reported: 2014-11-24 08:45 UTC by XiongZhang
Modified: 2015-03-06 23:53 UTC (History)
0 users

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Description XiongZhang 2014-11-24 08:45:10 UTC
Hardware:SandyBridge

the score of running "glmark2 --off-screen":
mesa 10.2: 1412
mesa 10.3 or master: 979

Through bisect, I found the bad commit is:
commit 2f28a0dc23165123cf1e8b5942acad37878edd8a
Author: Kristian Høgsberg <krh@bitplanet.net>
Date:   Mon Jul 7 16:44:58 2014 -0700

    i965: Implement fast color clears using meta operations


I did the following test to confirm this regression is introduced by commit 2f28a0d
1) git checkout 2f28a0d
   git revert 2f28a0d
   the score is 1412

2) git checkout 2f28a0d
   git am 14c1a2a9
   the score is 1052
Comment 1 Matt Turner 2015-03-06 23:53:12 UTC
I think this was fixed by this commit:

commit f95733ddb7fff0af923fce3a07ebef78fa3139a4
Author: Kenneth Graunke <kenneth@whitecape.org>
Date:   Fri Jan 9 20:46:17 2015 -0800

    i965: Respect the no_8 flag on Gen6, not just Gen7+.
    
    When doing repclears, we only want to use the SIMD16 program, not the
    SIMD8 one.  Kristian added this to the Gen7+ code, but apparently we
    missed it in the Gen6 code.  This patch copies that code over.
    
    Approximately doubles the performance in a clear microbenchmark from
    mesa-demos (clearspd -width 500 -height 500 +color) on Sandybridge.
    
    Cc: "10.4 10.3" <mesa-stable@lists.freedesktop.org>
    Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
    Reviewed-by: Kristian Høgsberg <krh@bitplanet.net>
    Reviewed-by: Matt Turner <mattst88@gmail.com>
    References: https://code.google.com/p/chrome-os-partner/issues/detail?id=34681


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