Bug 20333 - EXA is awefully slow for kde-base/kstars-3.5.10
Summary: EXA is awefully slow for kde-base/kstars-3.5.10
Status: RESOLVED WONTFIX
Alias: None
Product: xorg
Classification: Unclassified
Component: Server/Acceleration/EXA (show other bugs)
Version: 7.4 (2008.09)
Hardware: x86 (IA32) Linux (All)
: medium normal
Assignee: Xorg Project Team
QA Contact: Xorg Project Team
URL:
Whiteboard:
Keywords: NEEDINFO
Depends on:
Blocks:
 
Reported: 2009-02-26 10:55 UTC by Toralf Förster
Modified: 2009-03-27 11:52 UTC (History)
0 users

See Also:
i915 platform:
i915 features:


Attachments
xorg.conf (1.80 KB, text/plain)
2009-02-26 10:55 UTC, Toralf Förster
no flags Details
/var/tmp/Xorg.0.log.EXA (31.01 KB, text/plain)
2009-02-26 12:52 UTC, Toralf Förster
no flags Details
/var/tmp/Xorg.0.log.XAA (31.25 KB, text/plain)
2009-02-26 12:52 UTC, Toralf Förster
no flags Details

Description Toralf Förster 2009-02-26 10:55:04 UTC
Created attachment 23329 [details]
xorg.conf

I've a ThinkPad T41 :

tfoerste@n22 ~ $ /usr/sbin/lspci | grep VGA
01:00.0 VGA compatible controller: ATI Technologies Inc Radeon RV250 [Mobility FireGL 9000] (rev 02)
tfoerste@n22 ~ $ uname -a
Linux n22 2.6.27-gentoo-r9 #1 Sat Feb 21 15:39:26 CET 2009 i686 Intel(R) Pentium(R) M processor 1700MHz GenuineIntel GNU/Linux


and wondering why KStars is awefully slowly for EXA, while XAA works flawelessly if I choose to change the view direction. The other KDE desktop programs however are as fast as before (KDE, konqueror, firefox, vlc, flash etc).

I run a mostly stable Gentoo system w/ :

x11-base/xorg-server-1.5.3-r2
x11-drivers/xf86-video-ati-6.11.0
...
Comment 1 Michel Dänzer 2009-02-26 11:38:41 UTC
I noticed that kstars 4.2 is quite slow and uses a lot of CPU, but I just downgraded to 3.5.9 and it seems reasonably fast. Please provide specific steps for reproducing the problem and precise criteria for expected vs. observed behaviour.

Also please attach the Xorg.0.log with EXA enabled.
Comment 2 Toralf Förster 2009-02-26 12:52:15 UTC
Created attachment 23336 [details]
/var/tmp/Xorg.0.log.EXA

(In reply to comment #1)
> I noticed that kstars 4.2 is quite slow and uses a lot of CPU, but I just
Yep, CPU is stressed w/ EXA.

> Please provide specific steps for reproducing the problem and precise criteria for expected vs. observed behaviour.

steps o reproduce :

Start X11 with the EXA enabled xorg.conf (remove comment sign from line 82 of the already attached xorg.conf), log in into KDE, start KStars and change view direction from SOuth to North or from West to East - with EXA yyou now can take a cup of coffee until the step is done, w/ XAA however KStars runs fine.
Comment 3 Toralf Förster 2009-02-26 12:52:38 UTC
Created attachment 23337 [details]
/var/tmp/Xorg.0.log.XAA
Comment 4 Michel Dänzer 2009-02-27 06:55:51 UTC
(In reply to comment #2)
> change view direction from SOuth to North or from West to East - with EXA yyou
> now can take a cup of coffee until the step is done, w/ XAA however KStars runs
> fine.

Assuming 'change view direction' means dragging the mouse with the left button pressed, I can't reproduce this with either version of kstars.

Looking at your EXA log file:

(II) RADEON(0): Will use 6600 kb for front buffer at offset 0x00000000
[...]
(II) RADEON(0): Will use 6472 kb for X Server offscreen at offset 0x019ae000

The EXA offscreen memory area can't even hold a single pixmap corresponding to a screen-sized window. If adding

    Option "AccelDFS"
    Option "FBTexPercent" "0"

doesn't help, maybe try reducing the max desktop size or colour depth, or just stick to XAA.
Comment 5 Toralf Förster 2009-02-27 07:13:18 UTC
(In reply to comment #4)

> Assuming 'change view direction' means dragging the mouse with the left button
> pressed, I can't reproduce this with either version of kstars.
No, I meant "Pointing" -> "East"|"North"|"West"|"South"

> Looking at your EXA log file: If adding
> 
>     Option "AccelDFS"
>     Option "FBTexPercent" "0"
> 
> doesn't help
This helped :-)
With these 2 lines EXA is nearly as fast as XAA (btw the CPU still is stressed for some seconds).
Comment 6 Michel Dänzer 2009-02-27 07:22:54 UTC
(In reply to comment #5)
> > 
> >     Option "AccelDFS"
> >     Option "FBTexPercent" "0"
> > 
> > doesn't help
> This helped :-)
> With these 2 lines EXA is nearly as fast as XAA (btw the CPU still is stressed
> for some seconds).

Glad to hear it. I'm resolving this report as WONTFIX, as EXA relies on offscreen memory for acceleration. Hopefully in the future, when the drivers use kernel memory management, it'll no longer be necessary to use these options.

That said, you may also want to try xserver 1.6, there were some EXA performance improvements.
Comment 7 Toralf Förster 2009-03-27 11:52:08 UTC
FWIW with x11-drivers/xf86-video-ati-6.12.1 now it works w/o to tweak the xorg.conf :-)


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