[Bug 682338] Re: GTK programs in Ubuntu 10.10 are sluggish over NX
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Wed Jan 4 20:50:06 UTC 2012
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On 2010-12-01T12:12:12+00:00 Ryan Prichard wrote:
I use NX to connect to a work computer from home, over the Internet. I
recently upgraded to Ubuntu 10.10, and I noticed that GTK programs
became very sluggish.
I currently have 1.10.0-1ubuntu3 of libcairo2 installed. If I override
this with the Ubuntu 10.04 version of libcairo2, 1.8.10-2ubuntu1,
performance is restored. I used LD_LIBRARY_PATH to run GTK programs with
the old libcairo2 package.
I first reported this issue against Ubuntu 10.10, but since the problem
is in Cairo (or NX), an Ubuntu maintainer suggested I report it here.
The Ubuntu bug report is at
https://bugs.launchpad.net/ubuntu/+source/cairo/+bug/682338. It has a
video attached demonstrating how much faster gedit is using the old
libcairo2 package.
Both the home and work computer run Ubuntu 10.10.
In addition to the performance drop, I see JPEG artifacts on rendered
text and metacity window decorations. I'm used to seeing some artifacts
because NX compresses things like icons with JPEG. NX doesn't normally
compress text, window decorations, etc. The slow performance and
artifacts suggests that NX is transmitting bitmap data when it should be
transmitting drawing commands.
The work computer has these NX packages installed:
nxclient-3.4.0-7
nxnode-3.4.0-14
nxserver-3.4.0-14
The home computer only has the nxclient-3.4.0-7 package installed.
The ping times from my home computer to work computer are about 35ms.
I made a Cairo Git checkout and verified that when I built 1.8.10, gedit
was fast, but when I built the newest version, gedit was slow. git
bisect identified a single commit where the performance problem began:
commit 33be73dfb76c26e3bb0ab59b2f570d00d9c7be62
Author: Chris Wilson <chris at chris-wilson.co.uk>
Date: Fri Sep 11 14:59:58 2009 +0100
[xlib] Fix big-line.
Project lines that exceed the 16.16 limits onto the XFixedLine, as we know
that top/bottom must fit within the confines of the surface and so will be
less than 16 bits.
Sadly this is a run-on patch that also does:
1. Make FillTiled the default for new GCs.
2. Stores extend mode as opposed to repeat, and thereby cleaning up some
inconsistent code.
3. Remove the special casing for unbounded trapezoids, as it is redundant
with the polygon clipping.
4. Tidy the logic for deciding when to use the core protocol
(_categorize_composite_operation)
When I searched the Internet for "Ubuntu 10.10 slow NX", I noticed a similar-looking problem reported on a forum.
- http://ubuntuforums.org/showthread.php?t=1625513
Reply at: https://bugs.launchpad.net/libcairo/+bug/682338/comments/3
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On 2011-05-09T03:07:04+00:00 Levi Purvis wrote:
I can confirm this bug. I have the same problem and it is resolved by
downgrading cairo to 1.8.10.
Reply at: https://bugs.launchpad.net/libcairo/+bug/682338/comments/7
------------------------------------------------------------------------
On 2011-05-09T13:02:47+00:00 Pavel-sidlo wrote:
I have the same problem. Downgraded Cairo to 1.8.10 too.
Reply at: https://bugs.launchpad.net/libcairo/+bug/682338/comments/8
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On 2011-06-18T19:39:42+00:00 Steven Robertson wrote:
This appears to be due to having 'display->buggy_repeat' set in
_cario_xlib_device_create(). NX (3.5, at least) presents itself as an
X.Org server with version 60900000, which trips the 'buggy_repeat' flag.
'buggy_repeat' is set on X.Org 6.9 to avoid a bug which will crash the X
server. On NX 3.5, running the 'extend-reflect' test case after forcing
the buggy_repeat flag to FALSE on git rev ced061124d0b402c did not crash
the X server, so it is possible this bug does not need to be worked
around on NX servers. (The test application crashes on svg11 and svg12
test modes, and fails on others, but it doesn't crash the X server
itself. Plus, NX fails many other tests, and other tests *will* crash
the server; not exactly a bastion of correctness.)
Cairo will use software compositing for some operations, preventing NX
from doing its X11 protocol compression magic to send text in an
efficient manner. The commit indicated by Ryan Prichard causes more
operations than before to use software compositing. I'm not sure if this
was intentional or not.
I see three reasonable solutions:
* Get NoMachine to update NX's reported version number. My current
employer makes extensive use of NX; I'll try to have someone talk to
them about this.
* Detect and whitelist NX for buggy_repeat using an out-of-band
mechanism.
* Revert to the (possibly incorrect?) stricter test for falling back to
software rendering.
In the mean-time, users can apply this patch to Cairo to work around the
workaround. I'm not recommending that this patch be applied to Cairo
itself, it's just for NX users who can't stand the slowness. Applies to
current git HEAD, but probably works fine with 1.10 too.
diff --git a/src/cairo-xlib-surface.c b/src/cairo-xlib-surface.c
index f8caf83..ffaa344 100644
--- a/src/cairo-xlib-surface.c
+++ b/src/cairo-xlib-surface.c
@@ -1994,8 +1994,8 @@ _recategorize_composite_operation (cairo_xlib_surface_t *dst,
return DO_XTILE;
}
- if (dst->buggy_repeat && src_attr->extend == CAIRO_EXTEND_REPEAT)
- return DO_UNSUPPORTED;
+ //if (dst->buggy_repeat && src_attr->extend == CAIRO_EXTEND_REPEAT)
+ //return DO_UNSUPPORTED;
if (! CAIRO_SURFACE_RENDER_HAS_COMPOSITE (src))
return DO_UNSUPPORTED;
Reply at: https://bugs.launchpad.net/libcairo/+bug/682338/comments/9
------------------------------------------------------------------------
On 2011-06-20T08:42:02+00:00 Ranma42 wrote:
(In reply to comment #3)
> This appears to be due to having 'display->buggy_repeat' set in
> _cario_xlib_device_create(). NX (3.5, at least) presents itself as an X.Org
> server with version 60900000, which trips the 'buggy_repeat' flag.
>
> 'buggy_repeat' is set on X.Org 6.9 to avoid a bug which will crash the X
> server. On NX 3.5, running the 'extend-reflect' test case after forcing the
> buggy_repeat flag to FALSE on git rev ced061124d0b402c did not crash the X
> server, so it is possible this bug does not need to be worked around on NX
> servers. (The test application crashes on svg11 and svg12 test modes, and fails
> on others, but it doesn't crash the X server itself. Plus, NX fails many other
> tests, and other tests *will* crash the server; not exactly a bastion of
> correctness.)
>
> Cairo will use software compositing for some operations, preventing NX from
> doing its X11 protocol compression magic to send text in an efficient manner.
> The commit indicated by Ryan Prichard causes more operations than before to use
> software compositing. I'm not sure if this was intentional or not.
>
> I see three reasonable solutions:
>
> * Get NoMachine to update NX's reported version number. My current employer
> makes extensive use of NX; I'll try to have someone talk to them about this.
>
> * Detect and whitelist NX for buggy_repeat using an out-of-band mechanism.
>
> * Revert to the (possibly incorrect?) stricter test for falling back to
> software rendering.
Another (untested) possibility is to use the xlib-xcb functions.
Is NX sluggish on a cairo library compiled with --enable-xlib-xcb ?
>
> In the mean-time, users can apply this patch to Cairo to work around the
> workaround. I'm not recommending that this patch be applied to Cairo itself,
> it's just for NX users who can't stand the slowness. Applies to current git
> HEAD, but probably works fine with 1.10 too.
>
> diff --git a/src/cairo-xlib-surface.c b/src/cairo-xlib-surface.c
> index f8caf83..ffaa344 100644
> --- a/src/cairo-xlib-surface.c
> +++ b/src/cairo-xlib-surface.c
> @@ -1994,8 +1994,8 @@ _recategorize_composite_operation (cairo_xlib_surface_t
> *dst,
> return DO_XTILE;
> }
>
> - if (dst->buggy_repeat && src_attr->extend == CAIRO_EXTEND_REPEAT)
> - return DO_UNSUPPORTED;
> + //if (dst->buggy_repeat && src_attr->extend == CAIRO_EXTEND_REPEAT)
> + //return DO_UNSUPPORTED;
>
> if (! CAIRO_SURFACE_RENDER_HAS_COMPOSITE (src))
> return DO_UNSUPPORTED;
Reply at: https://bugs.launchpad.net/libcairo/+bug/682338/comments/10
------------------------------------------------------------------------
On 2011-06-21T05:29:05+00:00 Steven Robertson wrote:
It certainly seems to have an effect - reliable server crash when
launching GEdit with git rev ced061124d0b402c is compiled with --enable-
xlib-xcb (binary loaded via LD_LIBRARY_PATH, so crash is probably not
gedit-specific). I can try to scrounge up additional information if it's
needed here, but with NX being quasi-closed-source it may not be easy or
helpful to do so.
Although it does end up crashing *very* quickly, so it solves the
performance problem in one sense.
Reply at: https://bugs.launchpad.net/libcairo/+bug/682338/comments/11
------------------------------------------------------------------------
On 2011-06-21T07:00:41+00:00 Ranma42 wrote:
(In reply to comment #5)
> It certainly seems to have an effect - reliable server crash when launching
> GEdit with git rev ced061124d0b402c is compiled with --enable-xlib-xcb (binary
> loaded via LD_LIBRARY_PATH, so crash is probably not gedit-specific). I can try
> to scrounge up additional information if it's needed here, but with NX being
> quasi-closed-source it may not be easy or helpful to do so.
A server crash should never happen, no matter what the application does.
If it is easy to reproduce, it might be an useful bugreport for NX developers.
>
> Although it does end up crashing *very* quickly, so it solves the performance
> problem in one sense.
Reply at: https://bugs.launchpad.net/libcairo/+bug/682338/comments/12
------------------------------------------------------------------------
On 2012-01-03T14:56:22+00:00 Manuel Siggen wrote:
NX developers have been informed :
http://www.nomachine.com/tr/view.php?id=TR01J02646
Reply at: https://bugs.launchpad.net/libcairo/+bug/682338/comments/13
------------------------------------------------------------------------
On 2012-01-04T04:54:32+00:00 Levi Purvis wrote:
The quick-fix patch suggested in comment #3 resolved the issue for me in
Ubuntu 11.10. I applied the patch against Ubuntu's cairo source package
1.10.2-6ubuntu3 (the offsets had to be adjusted a bit).
Reply at: https://bugs.launchpad.net/libcairo/+bug/682338/comments/14
** Bug watch added: www.nomachine.com/tr/ #TR01J02646
http://www.nomachine.com/tr/view.php?id=TR01J02646
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https://bugs.launchpad.net/bugs/682338
Title:
GTK programs in Ubuntu 10.10 are sluggish over NX
Status in libcairo - cairo vector graphics library:
Confirmed
Status in “cairo” package in Ubuntu:
Triaged
Status in “cairo” source package in Precise:
Triaged
Bug description:
I use NX to connect to a work computer from home, over the Internet.
I recently upgraded to Ubuntu 10.10, and I noticed that GTK programs
became very sluggish.
I currently have 1.10.0-1ubuntu3 of libcairo2 installed. If I
override this with the Ubuntu 10.04 version of libcairo2,
1.8.10-2ubuntu1, performance is restored. I used LD_LIBRARY_PATH to
run GTK programs with the old libcairo2 package.
I'll attach a video demonstrating how much faster gedit is using the
old libcairo2 package.
Both my home and work computer run Ubuntu 10.10.
The work computer has these NX packages installed:
nxclient-3.4.0-7
nxnode-3.4.0-14
nxserver-3.4.0-14
The home computer only has the nxclient-3.4.0-7 package installed.
The ping times from my home computer to work computer are about 35ms.
I suspect this issue is related to, or a duplicate of, bug #595845.
ProblemType: Bug
DistroRelease: Ubuntu 10.10
Package: libcairo2 1.10.0-1ubuntu3
ProcVersionSignature: Ubuntu 2.6.35-22.35-generic-pae 2.6.35.4
Uname: Linux 2.6.35-22-generic-pae i686
NonfreeKernelModules: nvidia
Architecture: i386
Date: Sun Nov 28 03:23:50 2010
InstallationMedia: Ubuntu 10.10 "Maverick Meerkat" - Release i386 (20101007)
ProcEnviron:
PATH=(custom, user)
LANG=en_US.utf8
SHELL=/bin/bash
SourcePackage: cairo
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