Improve (potentially halve) login time by using readahead

[jw5801]

(2) In Intrepid, there is a new tweak to the default readahead lists in that they removed all the kernel modules from the readahead list (i.e. files ending in .ko) which is supposed to improve bootup speed -- rarely are all the kernel modules required during bootup, but they are all touched a little bit by udev. If you try filtering out *.ko, it might improve boot speed a bit too.

Good call, worthy of being added to the original post. Not applicable to using readahead for login, but could be useful while profiling the boot sequence. Could use the following to automate the filtering:

sed -i -e 's/^.*.ko$//' /etc/readahead/boot

Is there a way to tell sed to replace a pattern with a reverse line feed? That would be useful to prevent blank lines in the file.

If you want to get really finicky you could always leave in the modules you know you'll use. The command below should return a list of the kernel modules you're currently using which would be ready to add to a readahead list.

lsmod | sed 's/^\([a-zA-Z1-9]\{1,\}\).*/\1.ko/' | more +2 | xargs locate | grep $(uname -r)