Re: [gentoo-user] Problems with MAKEOPTS -j

[Michael Mol <mikemol@gmail.com>]

On Thu, Aug 25, 2011 at 3:37 AM, Pandu Poluan <pandu@poluan.info> wrote:
> Have anyone experienced problems with MAKEOPTS?
>
> I have a quad-core system, so I put in "-j5". But that resulted in
> emerge fails for binutils and ppl. I have to change it to "-j3" before
> ppl can be emerged, even "-j1" before binutils can be emerged.
>
> Anyone experiencing the same?

Sometimes. My understanding is that it comes from packages which are
badly constructed, and can't reliably handle parallel builds. I'm told
that these cases are bugs and should be reported. Sometimes, if I
watch build output fly by, I'll even see something like

make -j10 -j1 (some target name)

where a maintainer decided to put an overriding -j1 after MAKEOPTS.


About two years ago, I found that, on my system (quad-core AMD Phenom
9650), -j8 resulted in the fastest build time, as measured by building
ffmpeg.[1] Currently, I'm running -j10, and that's because I've been
using distcc to pass a couple compile tasks off to other systems.
(Though with the box I was deferring to scrapped for parts, I'll drop
this down to -j8 again)

[1] Tested by building in tmpfs. You can find my data here:
http://multimedia.cx/eggs/ffmpeg-and-multiple-build-threads/#comment-150325

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:wq