Bug#408759: closed by Guillaume Delacour <gui at iroqwa.org> (Closed because gnome-terminal 2.14 is outdated.)

[Paul Szabo]

Dear Guillaume,

The question is not whether 2.14 is outdated, but whether the bug has
miraculously fixed itself in later versions.

> $ time perl -e '$|=0; foreach $x (1..500) { print "x" foreach(1..$x);
> print " $x\n" }'
> (snip)
> real	0m0.458s
> on Intel(R) Core(TM)2 CPU         T7400  @ 2.16GHz

I am not impressed. The bug better exhibits itself with $|=1.

Testing my ancient "Intel(R) Pentium(R) 4 CPU 2.40GHz stepping 04" with
"MSI 6526G-L with 845G chipset" motherboard and using the builtin video
controller, running Ubuntu hardy with i810 driver, I get:

Running rxvt:

psz at ASI:~$ ps --no-headers -p $PPID
 5701 pts/2    00:00:03 rxvt
psz at ASI:~$ time perl -e '$|=0; foreach $x (1..500) { print "x" foreach(1..$x); print " $x\n" }'
real	0m0.064s

and that may be a good benchmark (anything slower being unacceptable?).
Even rxvt with flushed output is bad:

psz at ASI:~$ ps --no-headers -p $PPID
 5701 pts/2    00:00:03 rxvt
psz at ASI:~$ time perl -e '$|=1; foreach $x (1..500) { print "x" foreach(1..$x); print " $x\n" }'
real	0m0.509s

Trying xterm, is not impressive:

psz at ASI:~$ ps --no-headers -p $PPID
 5624 ?        00:00:08 xterm
psz at ASI:~$ time perl -e '$|=0; foreach $x (1..500) { print "x" foreach(1..$x); print " $x\n" }'
real    0m0.683s
psz at ASI:~$ time perl -e '$|=1; foreach $x (1..500) { print "x" foreach(1..$x); print " $x\n" }'
real    0m0.766s

while gnome-terminal is hopeless:

psz at ASI:~$ dpkg -l gnome-terminal
ii  gnome-terminal 2.22.1-0ubuntu The GNOME 2 terminal emulator application
psz at ASI:~$ ps --no-headers -p $PPID
 5637 pts/1    00:00:04 gnome-terminal
psz at ASI:~$ time perl -e '$|=0; foreach $x (1..500) { print "x" foreach(1..$x); print " $x\n" }'
real	0m0.932s
psz at ASI:~$ time perl -e '$|=1; foreach $x (1..500) { print "x" foreach(1..$x); print " $x\n" }'
real	0m1.184s

Please comment on why does flushed output take so long in the X server,
and why is gnome-terminal so inefficient. Actually improving them would
be appreciated.

Please re-open bug.

Thanks, Paul

Paul Szabo   psz at maths.usyd.edu.au   http://www.maths.usyd.edu.au/u/psz/
School of Mathematics and Statistics   University of Sydney    Australia