X11 clients use blocking sockets causing large drawing times

Hi mike-kleinnet,

Please attach the output of `lspci -vvnn`, and attach your /var/log/Xorg.0.log file from after reproducing this issue. If you've made any customizations to your /etc/X11/xorg.conf please attach that as well.

Please attach the output of `lspci -vvnn` too.

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I've attached the requested files, although this issue appears to be in the X client libraries, not the server.

Thanks; I'm guessing this may be another instance of bug #277069 ? The symptoms sound similar anyway. Can you try running with a non-xcb libx11 and see if that makes the problem go away?

Hi Bryce -- I'm not sure what a non-xcb libx11 is... where would I find one and how would I replace it?

Looking over the other related bug reports, it does not seem like the same problem. This one is very specific to X text drawing commands.

  -Mike

On 2/27/2009 10:40 AM, Bryce Harrington wrote:
> Thanks; I'm guessing this may be another instance of bug #277069 ? The
> symptoms sound similar anyway. Can you try running with a non-xcb
> libx11 and see if that makes the problem go away?
>

This is as said a duplicate of bug #277069 and enabling TCP_NODELAY in libxcb fixes the problems. I posted a patch for it on the freedesktup bug mentioned in #277069, and there is a ppa deb packege for it there too.

This bug report was filed against an old version of Ubuntu.
Can you confirm whether this is still an issue in natty?

If you don't mind, it would be very helpful if you could update the bug
report in launchpad to 'Fix Released' if it is no longer an issue for
you, or if it is still occurring under natty, please tag the bug 'natty'
so it's easier for us to track.

I am still using 8.04 so yes, it is still an important issue for me. It is unrealistic to upgrade 5 or 6 versions of Ubuntu just to test this, since upgrading all associated applications, scripts, maintenance methods, etc. would be required.

Please note that this bug was filed over 2 years ago and no progress has been made.

  -Mike

On Apr 27, 2011, at 8:38 PM, bugbot wrote:

> This bug report was filed against an old version of Ubuntu.
> Can you confirm whether this is still an issue in natty?
>
> If you don't mind, it would be very helpful if you could update the bug
> report in launchpad to 'Fix Released' if it is no longer an issue for
> you, or if it is still occurring under natty, please tag the bug 'natty'
> so it's easier for us to track.
>
>
> ** Changed in: libx11 (Ubuntu)
> Status: Confirmed => New
>
> ** Changed in: libx11 (Ubuntu)
> Status: New => Incomplete
>
> --
> You received this bug notification because you are a direct subscriber
> of the bug.
> https://bugs.launchpad.net/bugs/320150
>
> Title:
> X11 clients use blocking sockets causing large drawing times
>
> Status in “libx11” package in Ubuntu:
> Incomplete
>
> Bug description:
> Binary package hint: libx11-6
>
> Description: Ubuntu 8.04.2
> Release: 8.04
>
> libx11-6:
> Installed: 2:1.1.3-1ubuntu2
> Candidate: 2:1.1.3-1ubuntu2
> Version table:
> *** 2:1.1.3-1ubuntu2 0
> 500 http://us.archive.ubuntu.com hardy/main Packages
> 100 /var/lib/dpkg/status
>
> Symptoms: very slow drawing times for text strings in X clients,
> restored to normal if mouse moves over the X client's window while
> drawing. Originally seen in charts produced in the scilab
> application, but underlying problem appears to exist in all X clients
> due to Hardy X11 runtime library problem. This problem did not exist
> in Gutsy (I recently upgraded).
>
> Cause: strace shows that X clients under Ubuntu 8.04 do not set X
> client-server socket's TCP_NODELAY option. Therefore X server can
> potentially wait until X server's timeout before sending ACK packet
> back to X client. This occurs in some (or all) X text drawing
> commands which do not require a reply, therefore waiting for the ACK
> until the next packet happens to be sent from X server back to X
> client. Under Windows this delay is 200 ms, causing extremely slow
> drawing times if the window contains a lot of text. ACK delay under
> Hardy is very small (< 1 ms), making this issue imperceptible when X
> server is also running (displaying) on a Hardy machine.
>
> Strace run on Ubuntu 8.04 contains this trace for opening the socket
> to the X server:
>
> 6246 socket(PF_INET, SOCK_STREAM, IPPROTO_TCP) = 3
> 6246 connect(3, {sa_family=AF_INET, sin_port=htons(6000), sin_addr=inet_addr("192.168.0.14")}, 16) = 0
> 6246 getpeername(3, {sa_family=AF_INET, sin_port=htons(6000), sin_addr=inet_addr("192.168.0.14")}, [16]) = 0
>
>
> The same startup on RedHat:
>
> [pid 8014] socket(PF_INET, SOCK_STREAM, IPPROTO_IP) = 3
> [pid 8014] setsockopt(3, SOL_TCP, TCP_NODELAY, [1], 4) = 0
> [pid 8014] setsockopt(3, SOL_SOCKET, SO_KEEPALIVE, [1], 4) = 0
> ...