** Changed in: libx11 (Fedora) Importance: Unknown => High -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to libxcb in Ubuntu. https://bugs.launchpad.net/bugs/277069
Title: Slow performance with remote X applications (java, firefox/xul, etc.) Status in libxcb: Fix Released Status in ia32-libs package in Ubuntu: Fix Released Status in libx11 package in Ubuntu: Invalid Status in libxcb package in Ubuntu: Fix Released Status in ia32-libs source package in Hardy: Won't Fix Status in libx11 source package in Hardy: Invalid Status in libxcb source package in Hardy: Won't Fix Status in ia32-libs source package in Intrepid: Invalid Status in libx11 source package in Intrepid: Invalid Status in libxcb source package in Intrepid: Invalid Status in ia32-libs source package in Jaunty: Won't Fix Status in libx11 source package in Jaunty: Invalid Status in libxcb source package in Jaunty: Won't Fix Status in ia32-libs source package in Karmic: Fix Released Status in libx11 source package in Karmic: Invalid Status in libxcb source package in Karmic: Fix Released Status in Debian: Fix Released Status in libx11 package in Fedora: Fix Released Status in Suse: New Bug description: With xcb every write (in _XFlush) is followed by a read (_XEventsQueued) which is the cause of the very poor performance. The read usually returns EAGAIN because there is nothing to be read, but it is a severe performace hit anyhow. And why _XEvenetsQueued/read is being called when select/poll has previously returned indicating only a single file descriptor was ready is anybody's guess. [Original Report] I've submitted this bug as https://bugs.freedesktop.org/show_bug.cgi?id=17868 as well. Though the problem may not be in ia32-libs -package, it contains the /usr/lib32/libX11.so.6.2.0 library that appears to be somehow relevant to the problem at hand. Some Java applications, such as the trial version in http://www.typingmaster.com/, run unusably slow when used over a remote X connection. I'm using Ubuntu Hardy 8.04.1 with LTSP5, Linux kernel 2.6.24-19-server, with 32-bit firefox and 32-bit Java-plugin. The relevant package versions are here: firefox32 2.0.0.17 sun-java32 1.6.0.5 sun-java6-jre 6-06-0ubuntu1 ia32-libs 2.2ubuntu11 The issue does not appear to be Java-version related (it exists in 1.5 and 1.6 versions). I have not tested the very latest Java-versions though. The reason I'm reporting this as a possible XCB-related issue is that one can workaround the problem by using an X11-library that does not link to XCB. In current Ubuntu version (Hardy), /usr/lib32/libX11.so.6.2.0 library links to /usr/lib32/libxcb-xlib.so.0 and /usr/lib32/libxcb.so.1 libraries, XCB version is 1.1. In previous Ubuntu version (Gutsy) the X11-library does not do this. When the new library shared object replaced with the old one, the problem disappears, and Java applications that had problems run fine. There may be some other differences between the X11-libraries, but using XCB as an underlying implementation seems to be a major change, or is it? All other applications do not appear to have these problems, Java applications appear to be the sole source of these problems. I'm adding two attachments that show tshark-dump of network traffic in both cases, perhaps it helps to analyze the issue. What happens there is one keypress on typingmaster Java-version, on Hardy/XCB case it takes half a minute to process one keypress and switch a screen, on Gutsy/no-XCB case it takes maybe a second. Juha [lspci] 00:00.0 Host bridge [0600]: VIA Technologies, Inc. VT8623 [Apollo CLE266] [1106:3123] Subsystem: VIA Technologies, Inc. Unknown device [1106:0000] 01:00.0 VGA compatible controller [0300]: VIA Technologies, Inc. VT8623 [Apollo CLE266] integrated CastleRock graphics [1106:3122] (rev 03) (prog-if 00 [VGA controller]) Subsystem: VIA Technologies, Inc. VT8623 [Apollo CLE266] integrated CastleRock graphics [1106:3122] To manage notifications about this bug go to: https://bugs.launchpad.net/libxcb/+bug/277069/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
