On 2015-12-30 10:49:27 -0500, Tom Lane wrote: > > On Wed, Dec 30, 2015 at 5:44 PM, Andres Freund <and...@anarazel.de> wrote: > >> I still maintain that --enable-depend should be on by default. We're > >> absurdly optimizing towards saving a handful of cycles in scenarios > >> which are usually bottlenecked by other things (build boxes spend more > >> times on tests and such) > > Nonsense. The buildfarm will simply get slower, and at least for my > animals it's too damn slow already.
I think you're overstating the performance impact of --enable-depend. It's just an additional output file for the compiler, given the way we're doing it (-MMD -MP -MF $outfile). Let's make a quick test. I've built both trees once before, to prime ccache. The test is: for i in $(seq 1 5); do git clean -dfxq && ./configure --(dis|en)able-depend --quiet && time make -j4 -s;done (coffee break) no ccache, --disable-depend: 0m55.810s, 0m58.361s, 0m58.517s, 0m58.674s, 0m58.466s ccache, --disable-depend: 0m5.248s, 0m5.279s, 0m5.244s, 0m5.771s, 0m5.296s no ccache, --enable-depend: 0m56.443s, 0m58.507s, 0m58.587s, 0m58.866s, 0m58.429s ccache, --enable-depend: 0m5.538s, 0m5.518s, 0m5.572s, 0m5.555s, 0m5.528s Yes, this is on a much faster machine (my laptop) than what some buildfarm animal are running. But given it's really just some additional, *small*, files that are written (compiler) and read (make), I don't see why the impact would be significantly different on slower machines. > We could fix that by having the > buildfarm script automatically add --disable-depend; but if we're going > to change this, we should roll out that script update BEFORE we change > it, not after. Sounds reasonable, despite the above. This isn't an urgent change, just something to make newer developers waste less time. -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
