Re: [gentoo-user] nproc

[Waldo Lemmer <pugonfireyt@gmail.com>]

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Hi Jude,

I can't answer your question directly because, frankly, it doesn't make a
whole lot of sense. But I'll try my best to clear things up for you.

The `nproc` command prints how many processors (CPU cores) are available
for applications to use. This is how many emerge or make jobs can run in
parallel.

How many jobs actually run depends on the -j and -l values of both emerge
and make. emerge's -j and -l are passed on the command line or in
EMERGE_DEFAULT_OPTS in make.conf. make's -j and -l are passed in MAKEOPTS
in make.conf.

The following links cover the ideal values for these:

https://wiki.gentoo.org/wiki/EMERGE_DEFAULT_OPTS
https://wiki.gentoo.org/wiki/MAKEOPTS

As for my recommendation, I would go for the following (assuming nproc
outputs '8'):

    MAKEOPTS='--jobs=8 --load-average=8'
    EMERGE_DEFAULT_OPTS='--jobs=8'

Note that I didn't pass -l to emerge. I don't want to risk confusing you
further, so I won't explain my reasoning here. Anyone who's interested
should feel free to ask.

There has been a lot of discussion about the perfect values, with no real
consensus having been reached:

 - make -j8 -l8, emerge -j8,

 - make -j8 -l8, emerge -j8 -l8,

 - make -j8 -l9, emerge -j8 -l8,

 - make -j9 -l7, emerge -j9 -l7, etc.

My advice is to pick whatever feels right to you, and use genlop to measure
the differences if you really care about getting it exactly right. I'm
willing to bet you won't see more than 10% difference between the above
combinations for most runs of emerge.

I hope I've managed to identify and address your misunderstandings.

Waldo

On Tue, Jun 4, 2024, 18:20 Jude DaShiell <jdashiel@panix.com> wrote:

> How is the number of threads nproc can handle printed out to the terminal?
> On an earlier install try I had J7,l8 put in /etc/portage/make.conf since
> the computer has 14gb of available memory on it.
>
>
> --
>  Jude <jdashiel at panix dot com>
>  "There are four boxes to be used in defense of liberty:
>  soap, ballot, jury, and ammo.
>  Please use in that order."
>  Ed Howdershelt 1940.
>
>

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