I got a new Windows desktop last week, and was curious if enabling disk compression would have any effect on build times… The theory being that source code compresses well (binaries too, to a lesser degree), so less disk IO should result. The price is more CPU usage, but this is a Core i7 box, so that’s basically free.
Result: Theory Busted.
Without disk compression, a full build took 23 minutes. With disk compression, 24 minutes. [Drive formatted between tests.] I’d guess some combination of not being IO bound plus disk seeks dominate, so compression doesn’t really help and just adds overhead. I also tried disabling “write-cache buffer flushing” to no effect, although I’m curious if splitting my build across two drives will help at all [src on one, objdir on the other; currently it's in a RAID-0 config].
One thing that would be nice is if parallel make worked correctly with Mozilla on Windows. If I build with anything higher than MOZ_MAKE_FLAGS=”-j1″, the build hangs at random (?) places. Seeing as this is a quad-core box (8-core, if you count HT), that makes me all sad and frowny.
Update: Mitch on IRC pointed out bsmedberg’s pymake work. With -j1 it’s about 30 seconds slower, but with -j10 it did a full build in 11 minutes (without hanging like a gmake build did!). Yay! I should also note that until now I’ve been doing Windows builds in a VM, which can take well over an hour to finish.