#572911 Slow OpenGL with KMS/DRI2

Package:
xserver-xorg-video-radeon
Source:
xserver-xorg-video-ati
Description:
X.Org X server -- AMD/ATI Radeon display driver
Submitter:
"Alexey Feldgendler"
Date:
2010-04-13 15:33:06 UTC
Severity:
normal
#572911#5
Date:
2010-03-07 16:07:44 UTC
From:
To:
With KMS and DRI2, glxgears is dramatically slower (about 140 fps)
than without KMS and DRI2 and with only DRI (about 300 fps). Also, the
motion is not uniformly smooth and seems to depend a lot on the
background system activity. I have a shell script that updates the
clock in my dzen2 status bar once per second, and the gears seem to
stumble for a split second once per second as it happens. I tried
stopping that script, and have confirmed that it indeed is causing the
jitter, even though the load it puts on the system is tiny. This
didn't happen without KMS and DRI2; not only did the animation run
faster, but it was also smooth (without noticeable jitter).

The kernel is linux-image-2.6.33-2-686 from experimental, and
libgl1-mesa-dri is 7.7-4 from unstable.
#572911#10
Date:
2010-03-07 17:07:53 UTC
From:
To:
Alexey Feldgendler wrote:

glxgears is dramatically not a benchmark. Its fps output measures
nothing interesting in the real life. You should use a real 3D game or
whatever, but not glxgears.

Brice
#572911#15
Date:
2010-03-08 00:55:35 UTC
From:
To:
Alright, I admit this bug is invalid. I've run gtkperf, the best I could
find in Debian, and observed no statistically significant slowdown. Tried
to run these demos/benchmarks <http://unigine.com/download/> but couldn't
because they require the GL_ARB_map_buffer_range extension — don't know
what it is, but it sure isn't in my glxinfo output.
#572911#20
Date:
2010-03-08 05:46:45 UTC
From:
To:
Alexey Feldgendler wrote:
#572911#25
Date:
2010-03-19 15:02:03 UTC
From:
To:
reopen 572911
thanks

This issue happens to me, too. It is most definitely not solved.

Any OpenGL application I try has very poor performance when KMS is
enabled. Have tried glxgears (FPS drops from ~1500 to ~300), AisleRiot
(from gnome-games), and ZSNES.

Using a Radeon X1550 (RV516). System information attached.
#572911#32
Date:
2010-03-19 15:34:29 UTC
From:
To:
Alex Hvostov wrote:

There is nothing to solve in this report, glxgears is not a benchmark,
so having a "slow glxgears" means nothing. Moreover, you're not even
using KMS/DRI2, so your "problem" has nothing to do here.

cheers,
Brice
#572911#37
Date:
2010-03-19 15:39:23 UTC
From:
To:
Please reread my message. I am experiencing poor performance in
AisleRiot and ZSNES as well. This is when KMS is *on*; I experience no
such performance issue when KMS is off.

Honestly. This is insulting.
#572911#46
Date:
2010-03-19 15:49:57 UTC
From:
To:
Alex Hvostov wrote:

This bug report was about glxgears, not about these.

Why did you send the log with KMS off then...

Brice
#572911#51
Date:
2010-03-19 15:55:33 UTC
From:
To:
It seems to me that it's about poor OpenGL performance, with glxgears
being used as an example. That's certainly not the only application
suffering from poor performance.

My mistake. Sorry about that. Attached is the log with KMS on; I hope it
helps.
#572911#56
Date:
2010-03-19 16:26:13 UTC
From:
To:
glxgears is showing the same problem (very poor performance) as every
other application I've tested. How is that meaningless?

AisleRiot gets ~15-30 FPS, which is terrible considering it's just a
solitaire game. armagetronad locks up the entire X display for seconds
at a time, leaving only a split second between lock-ups where the mouse
cursor can be moved.

AisleRiot uses libclutter (and, therefore, OpenGL) for drawing. ZSNES
uses OpenGL as well. Both show very poor performance.
#572911#61
Date:
2010-04-13 15:31:56 UTC
From:
To:
This issue, I believe, is well known:

http://www.phoronix.com/scan.php?page=article&item=ati_ubuntu_kmsums&num=1

In my opinion this bug should be renamed to something like: degraded
performance of KMS vs UMS
And perhaps it should be put in wishlist and sent upstream.

Andres