| From | Andi Kleen <> | Subject | Re: [RFC PATCH 00/50] tools/perf: Speed up the build system | Date | Mon, 07 Oct 2013 13:15:59 -0700 |
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Ingo Molnar <mingo@kernel.org> writes: > > The series also includes a number of fixes and convenience features: > > - auto-detect the number of CPUs on the system and add the -j<cpus> > option automatically
FWIW I would prefer if you not do that automatically, because:
- Often the optimal factor is not 1, but something like 1.5*CPUs (but I'm not sure it's the same on all systems, probably depends on the IO capacity and memory) - It may use a lot of memory, so should be something controlled by the user. - Often it's useful to use a few threads less to avoid interactivity problems on a workstation. - With LTO there can be rare cases where you need to lower it to avoid running out of memory. - Kernel build users should be already trained to set that parameter and it's not really a big burden.
The rest looks like a great improvement.
-Andi
-- ak@linux.intel.com -- Speaking for myself only
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