Re: [gentoo-dev] [PATCH 2/3] multiprocessing.eclass: Introduce get_nproc() to get no of CPUs

[Andrew Savchenko]

On Wed, 14 Dec 2016 12:32:41 -0600 Nathan Zachary wrote:
> On 14/12/16 12:29, Fabian Groffen wrote:
> > On 14-12-2016 13:01:16 -0500, Doug Freed wrote:
> >> On Wed, Dec 14, 2016 at 12:48 PM, Nathan Zachary
> >> <nathanzachary@g.o> wrote:
> >>> On 14/12/16 10:11, Doug Freed wrote:
> >>>>> I somehow doubt that would give me the expected number only, and I lack
> >>>>> a BSD install handy to test it.
> >>>> $(sysctl -n hw.ncpu)
> >>>>
> >>> I don't know that the sysctl command works universally:
> >>>
> >>> # sysctl -n hw.ncpu
> >>> sysctl: cannot stat /proc/sys/hw/ncpu: No such file or directory
> >>>
> >> It's BSD-specific (Darwin may have it too, but I'm not in OS X at the
> >> moment, so I can't check), which pretty much describes this branch in
> >> the codepath as well.  Linux users will have the nproc command from
> >> coreutils.
> > Yes, Darwin has it too, but the tool lives in /usr/sbin instead:
> >
> > https://gitweb.gentoo.org/repo/proj/prefix.git/tree/scripts/bootstrap-prefix.sh#n1987
> >
> > Fabian
> >
> >
> Ah, yes, I missed the part about it being BSD-specific.
>
> This one-liner certainly isn't as graceful or elegant, but it works:
>
> # cat /proc/cpuinfo | grep 'processor' | wc -l
 
Not all BSD systems have procfs enabled.

Best regards,
Andrew Savchenko