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Shell startup times, part 2

Following up on Saturday's post and various other blog entries about bash.

While arguing with Anton about bash being slow, I discovered that /etc/bash_completion was sourced twice when starting a shell on my laptop; once in /etc/bash.bashrc, and once in ~/.bashrc. This is Debian bug #430501 - the suggestion there is that /etc/skel/.bashrc should change to check whether /etc/bash_completion had already been included. So, that saves 0.27 seconds.

tim@regulus:~$ time bash -i -c exit
exit

real	0m0.270s
user	0m0.240s
sys	0m0.032s

This is still ages when compared to zsh. A solution is proposed in Debian bug #467231 - the functions could be loaded dynamically when they are first used, instead of all at once. I may try this next.

One sandwich and cup of tea later: it works, and bash now beats zsh's time.

tim@regulus:~$ time bash -i -c exit
exit

real	0m0.047s
user	0m0.036s
sys	0m0.004s

Posted: 24 Mar 2008 00:00 | Tags: Planet WUGLUG, Planet UWCS, shell, bash, zsh | Comments (1)

Shell startup times

So, a benchmark.

tim@regulus:~$ time zsh -i -c exit

real    0m0.064s
user    0m0.048s
sys     0m0.008s

tim@regulus:~$ time bash -i -c exit
exit

real    0m0.540s
user    0m0.436s
sys     0m0.100s

Both shells had their respective completion systems enabled. (Without them turned on, bash actually beats zsh... but the times are small enough that it doesn't matter.) These times are with a warm disk cache - the first time through both shells were slower. And the numbers stay roughly the same when repeating.

Posted: 22 Mar 2008 00:00 | Tags: Planet WUGLUG, Planet UWCS, bash, zsh, shell | Comments (0)