On 11 Feb 2013, at 13:56, Fabian Keil <freebsd-lis...@fabiankeil.de> wrote:
> real 350m42.363s > user 253m5.477s > sys 50m0.024s These numbers look a bit wrong. You've got 300 minutes of CPU time, but 350 minutes of real time. In an ideal world, on your dual-core system you'd see 150 minutes of real time. Seeing more than 300 implies that you're spending a lot of time waiting for I/O. The normal recommendation is to use -j x where x is 1.5 times the number of cores, or 1x the number of GBs of RAM, whichever is smaller. With only 2GB of RAM you might have linking problems with -j3, but it's still worth trying. One of the more serious problems with our current build system is that it doesn't scale well to large numbers of cores. On a 32-core system, with -j64, we're very rarely managing to have even 8 things able to run in parallel. This should be addressed when the bmake import is fully integrated and we can use meta mode for better dependency tracking. Ninja has a concept of pools, so you can say 'only run one link job at a time, but you can do two C++ compile jobs or 4 C compile jobs', and it might be interesting to look at adding something similar to bmake, as this can improve scalability a lot. David _______________________________________________ freebsd-current@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org"
