* Xan Lopez wrote on Tue, Jan 04, 2011 at 02:21:01PM CET: > The system is Fedora 13 > with ext4, kernel 2.6.34, CPU i7 2.67Ghz and the HDD is a standard > laptop 7200rpm thingie. > > Without the local hack to get rid of the -MP flag a null-build with > that version of GNU make is ~40s. CVS HEAD gives ~26s (wow!), and CVS > HEAD with the "get rid of -MP" hack gives ~14s. So definitely there's > been a big improvement in Make in the last year, thanks for pointing > that out. It still seems worth to try to improve the -MP case though, > 26 > 14 is a big win.
> > Then, how many stub targets get added due to -MP in your project? > > Some grep hackery gives me 3,030,859 empty rules in total in all .Plo > files in the build tree. > > FWIW, on big systems I typically just put the build tree on a ramdisk > I've tried this and there's basically no perceptible difference > AFAICT. I only have the builddir in /dev/shm, since I don't think I > can fit the whole thing in RAM in my laptop. Hope it helps. Thanks for the data. This is a bug in GNU make. I'm working on a fix. Cheers, Ralf
