Andrew Dunstan <andrew@dunslane.net> writes:
> I have been investigating some build performance issues, and trying to
> narrow down causes of slowness, and observed an odd effect, which was
> suggested by a huge time difference between building from git and
> building from a tarball.
> If I do
> make -C src/port all
> and then wait 10 seconds or so and do
> make -j 3
> or even just plain
> make
> the build finishes much much faster (like 1m vs 5m) than if I had not
> run the first command.
Can't reproduce that here. What I do notice on a Fedora 14 machine is
that ccache seems to be enabled by default, ie you get caching even when
you just say "gcc", and that makes a huge difference in build times.
I see 70 seconds after "rm -rf ~/.ccache", versus 4 seconds with it
fully populated. Building src/port first saves nothing in either
starting state.
I wonder whether your experiments got affected by something similar.
regards, tom lane