Bug#265951: more info

[Lee Revell]

This is actually not a gnome-terminal problem, I was able to reproduce
the bug with xterm:

rlrevell@mindpipe:~$ time cat f
0       256
8       2
9       8
10      28
11      42
12      65
13      61
14      45
15      42
16      35
17      33
18      33
19      32
20      41
21      32
22      45
23      58
24      45
25      45
26      30
27      19
28      6
29      1
33      1
34      1
35      1
38      1
40      1
42      1
43      4
44      3
46      2
48      1
50      1
51      3
real    0m3.152s
user    0m0.002s
sys     0m0.004s

[subsequent runs]

real    0m0.005s
user    0m0.001s
sys     0m0.004s

real    0m3.154s
user    0m0.001s
sys     0m0.005s

real    0m0.005s
user    0m0.001s
sys     0m0.004s

real    0m0.005s
user    0m0.002s
sys     0m0.003s

real    0m3.153s
user    0m0.001s
sys     0m0.004s

So when it's 'fast' it takes .005/.001/.004 with a very slight variance,
and when it's 'slow' it takes 3.153s real +/- .002s!  This makes it
pretty clear that we either hit one code path or another, much slower
one.

Here are the libraries that gnome-terminal and xterm have in common:

        /lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x40000000)
        libICE.so.6 => /usr/X11R6/lib/libICE.so.6 (0x401c3000)
        libSM.so.6 => /usr/X11R6/lib/libSM.so.6 (0x401b9000)
        libX11.so.6 => /usr/X11R6/lib/libX11.so.6 (0x401f7000)
        libXext.so.6 => /usr/X11R6/lib/libXext.so.6 (0x401e9000)
        libXft.so.2 => /usr/lib/libXft.so.2 (0x40028000)
        libXrender.so.1 => /usr/lib/libXrender.so.1 (0x400ef000)
        libc.so.6 => /lib/tls/libc.so.6 (0x402fd000)
        libdl.so.2 => /lib/tls/libdl.so.2 (0x4044a000)
        libexpat.so.1 => /usr/lib/libexpat.so.1 (0x400cf000)
        libfontconfig.so.1 => /usr/lib/libfontconfig.so.1 (0x4003a000)
        libfreetype.so.6 => /usr/lib/libfreetype.so.6 (0x40061000)
        libncurses.so.5 => /lib/libncurses.so.5 (0x402be000)
        libz.so.1 => /usr/lib/libz.so.1 (0x40439000)

So the problem is either in one of the above libraries, or with the X
server itself, or the kernel.  For some reason Xrender seems like a good
place to start looking.

I am pretty sure this bug has been reported and widely discussed
elsewhere, with people attributing it to libvte, pango, and
gnome-terminal itself.

http://bugzilla.gnome.org/show_bug.cgi?id=122871
http://bugs.gnome.org/show_bug.cgi?id=137864
http://mail.gnome.org/archives/gnome-list/2004-July/msg00095.html

Lee