Random Efficiency Tips


You probably know the feeling when software you use daily gets in your way rather than assisting you. To me Emacs has been such an offender for a long time - in that it creates backup and semantic.cache files in every directory you edit files in. Obviously, this makes it often impossible to find the file you are looking for in a directory listing.

Last week I had enough and searched for a solution. I found one to the backup files problem in Xah Lee's Advanced Emacs Tips and got rid of semantic.cache by following a suggestion in the ECB FAQ to set semanticdb-default-save-directory. In both cases the functionality in question is not disabled, but the corresponding files are created in a directory somewhere in ~/.emacs.d/ which makes me a happy Emacs user again.

Another huge annoyance is the long time it takes current Linux distributions to boot. I remember how my old 350MHz Pentium II with its by today's standards dead slow harddisks booted in about 20 seconds from the Lilo prompt to the KDM/GDM login screen. Out of the box the Debian installation on my 2.4GHz Core 2 Duo workstation with its 7200RPM disks needs about twice as much time to get me to a graphical (GDM) login. After getting rid of a bunch of unnecessary init scripts I got that figure down to slightly less than 30 seconds. So, it's definitely worth the effort to review what init scripts are run and whether you really need them. I still don't find the result very satisfactory though.

Last but not least I'd like to recommend the tips over at lesswatts.org. Even if you don't have a recent enough kernel and userspace to benefit from CONFIG_NO_HZ etc. it's worth going through their Tips & Tricks section and looking for potential power savings. Personally, I found the suggestion to mount filesystems with the noatime option enabled very useful, not necessarily because it saves power, but because it significantly speeds up things like apt-cache search, access to the dpkg database, and loading all the .desktop files.