Bug 24571 - Slowing to a crawl
Summary: Slowing to a crawl
Status: RESOLVED INVALID
Alias: None
Product: xorg
Classification: Unclassified
Component: Server/DDX/dmx (show other bugs)
Version: git
Hardware: x86 (IA32) Linux (All)
: medium normal
Assignee: dmx-bugs
QA Contact: Xorg Project Team
URL:
Whiteboard: 2011BRB_Reviewed
Keywords:
Depends on:
Blocks:
 
Reported: 2009-10-16 08:35 UTC by Lee Leahu
Modified: 2018-06-12 18:43 UTC (History)
1 user (show)

See Also:
i915 platform:
i915 features:


Attachments
opreport output after starting Xdmx (39.89 KB, text/plain)
2009-10-20 14:33 UTC, Lee Leahu
no flags Details
opreport output after Xdmx has become very slow (140.69 KB, text/plain)
2009-10-20 14:33 UTC, Lee Leahu
no flags Details
show how long miMoveWindow ran (1.53 KB, text/plain)
2009-10-21 22:50 UTC, Lee Leahu
no flags Details
squashed debugging statements (30.43 KB, text/plain)
2009-10-22 14:36 UTC, Lee Leahu
no flags Details
temporary patch to prevent MotionNotify events from piling up (815 bytes, text/plain)
2009-10-22 18:10 UTC, Lee Leahu
no flags Details

Description Lee Leahu 2009-10-16 08:35:55 UTC
xorg-server - GIT Commit - 25344ba7f7845654364d62bf15322b3b79465bd9

Use KDE 3.5.10 as the window manager.

When Xdmx is started across multiple computers, moving windows across multiple machines / resizing windows works fast.

Everything then slows down over time until you finally notice that is almost unbearable how long it takes to simply move a while around or resize it.

At that point, when new windows launch and appear on the local display (the display that Xdmx is running on), they run fine.  As soon as you move then onto a display attached to a different computer - they get terribly slow.

What I mean by terribly slow, is you move the window a little bit and wait several seconds at least for the screen to re-draw.  Move it a little bit more and wait same amount of time.  Move it a lot and wait same amount of time.  Resize the window any amount and wait the same amount of time.

Kill Xdmx and restarting Xdmx and KDE resolves the problem for a short while until it slows down again.

I recall this same behaviour from the xorg-server 1.3 (X.Org 7.2 I think?) days as well.
Comment 1 Lee Leahu 2009-10-20 14:31:36 UTC
Actually, this doesn't require KDE.  Just long periods of use.

I will attach two log files - one profiling Xdmx just after startup, and another profiling it again after it has slowed down considerably.
Comment 2 Lee Leahu 2009-10-20 14:33:32 UTC
Created attachment 30595 [details]
opreport output after starting Xdmx
Comment 3 Lee Leahu 2009-10-20 14:33:59 UTC
Created attachment 30596 [details]
opreport output after Xdmx has become very slow
Comment 4 Lee Leahu 2009-10-21 22:50:50 UTC
Created attachment 30612 [details]
show how long miMoveWindow ran

Here's an interesting development.

I made the attached changes to xorg-server to help narrow down the ever increasing slowness of Xdmx....

After several hours of usage...depending on the application window that I'm moving across screens, I'm seeing over 100,000 micro seconds of processing time of miMoveWindow on roughly 1 of every 5 or 6 calls of that function. The more "heavy" programs like TaskJugglerUI, KWrite, etc... I'm seeing well over 300,000 micro seconds.
Comment 5 Lee Leahu 2009-10-22 14:36:50 UTC
Created attachment 30632 [details]
squashed debugging statements

Events on non-input backend displays are accumulating causing the slowness over time.

This patch applies to GIT Commit 1228e2d052f0bb98175c55c194340773b5fedb40.  It shows the call stack (# of calls, and processing time).  It clearly shows the slow down when run and how many events are in the queue that keep getting re-processed.
Comment 6 Lee Leahu 2009-10-22 18:10:00 UTC
Created attachment 30634 [details]
temporary patch to prevent MotionNotify events from piling up

I'm providing this in case anyone needs it until the real fix is found.
Comment 7 Jeremy Huddleston Sequoia 2011-10-16 23:24:36 UTC
So it sounds like this isn't an issue of the server slowing down "over time" 
but rather as it gets backlogged.  Once you let the backlog clear, performance 
returns, right?

What is your networking configuration?  Is it possible that the network is 
causing the bottleneck?
Comment 8 Adam Jackson 2018-06-12 18:43:16 UTC
Mass closure: This bug has been untouched for more than six years, and is not obviously still valid. Please file a new report if you continue to experience issues with a current server.


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