Hi, On Sat, Jan 25, 2014 at 03:27:42AM +0100, Jann Horn wrote: > These are patches that should apply to the sid branch of > git://anonscm.debian.org/apt/apt.git – I hope that this is the right way to > do this? Sure, that is fine. If you have a branch of your own you can also point us into the general direction of it if you like. :) > These patches reduce the startup time of apt-get by ~19% on my system. I > measured by first doing "apt-get source sl", then running this command: […] Do you have any special reason to pick this command? I forgot to remove the binary caches at first, which caused me to see no meaningful difference, but maybe my machine is just too quick¹. Removing both caches shows the difference through (for me ~10%, but in a 5 second run, so this is very close to your results). I checked with "apt-get check -s" as this just generates the caches (in memory if run as user) and does the dependency walk which is run by the other apt-get commands as basic setup. (¹ that I would ever be able to say that…) > What do you think? Rewriting the whole source like this would probably make it > much uglier, but IMO optimizing a few hot code paths this way should be fine. Did you tried it with some sort of tool or just by "guessing"? We had a while back similar improvements with our own tolower reimplementation, so as long as speedups are observable and are not to crude I have no problem with adding them. (Will follow up on the patches itself in a second) Best regards David Kalnischkies
Attachment:
signature.asc
Description: Digital signature