Tim Retout's www presence

Encryption and disk access

Beginning last night, I reinstalled my laptop. Normally, if it were just to clean up some packages, I wouldn't do this - the aim was more to try out removing the disk encryption that I was using, and the effect has been quite dramatic.

I worked out a while ago that the device-mapper encryption was slowing down disk access - with it gone, boot times are much shorter (and I don't have to type in a LUKS passphrase). GNOME loads a lot faster. Additionally, bash starts a lot quicker than it did. I suspect loading the bash completion routines takes quite a bit of disk access. Update: No, I just didn't have the bash-completion package installed. Bash is still slow. GNOME is still faster, though... for now.

So, I will probably keep my new install. I need to investigate encrypting a USB device and integrating that nicely with GNOME and gpg.

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

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)