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Re: gcc build / test times on multi-core hosts?
- From: Mattias Engdegård <mattias at virtutech dot se>
- To: gcc at gcc dot gnu dot org
- Date: Sat, 18 Feb 2006 12:06:39 +0000 (UTC)
- Subject: Re: gcc build / test times on multi-core hosts?
- References: <43F651AC.8050406@st.com> <43F67F26.30507@redhat.com>
Diego Novillo <dnovillo@redhat.com> writes:
>I/O is probably the biggest bottleneck, so if you have a fairly decent
>I/O system, you may find higher -jN numbers giving better results.
Yes, but there is also an effect in the opposite direction: higher
parallelism may compensate for slow I/O by keeping CPUs busy. My rule
of thumb, no doubt suboptimal, is to build with twice as many jobs as
there are cores.