Gentoo Archives: gentoo-dev

From: Francesco Riosa <vivo75@×××××.com>
To: gentoo development <gentoo-dev@l.g.o>
Subject: Re: [gentoo-dev] [PATCH 2/3] multiprocessing.eclass: Introduce get_nproc() to get no of CPUs
Date: Wed, 14 Dec 2016 18:42:11
Message-Id: CAD6zcDygoP2i07=Aun+AxhReXFZNqd5BUfanh1EjB4ttTG2seg@mail.gmail.com
In Reply to: Re: [gentoo-dev] [PATCH 2/3] multiprocessing.eclass: Introduce get_nproc() to get no of CPUs by Nathan Zachary
1 2016-12-14 19:32 GMT+01:00 Nathan Zachary <nathanzachary@g.o>:
2
3 > On 14/12/16 12:29, Fabian Groffen wrote:
4 > > On 14-12-2016 13:01:16 -0500, Doug Freed wrote:
5 > >> On Wed, Dec 14, 2016 at 12:48 PM, Nathan Zachary
6 > >> <nathanzachary@g.o> wrote:
7 > >>> On 14/12/16 10:11, Doug Freed wrote:
8 > >>>>> I somehow doubt that would give me the expected number only, and I
9 > lack
10 > >>>>> a BSD install handy to test it.
11 > >>>> $(sysctl -n hw.ncpu)
12 > >>>>
13 > >>> I don't know that the sysctl command works universally:
14 > >>>
15 > >>> # sysctl -n hw.ncpu
16 > >>> sysctl: cannot stat /proc/sys/hw/ncpu: No such file or directory
17 > >>>
18 > >> It's BSD-specific (Darwin may have it too, but I'm not in OS X at the
19 > >> moment, so I can't check), which pretty much describes this branch in
20 > >> the codepath as well. Linux users will have the nproc command from
21 > >> coreutils.
22 > > Yes, Darwin has it too, but the tool lives in /usr/sbin instead:
23 > >
24 > > https://gitweb.gentoo.org/repo/proj/prefix.git/tree/
25 > scripts/bootstrap-prefix.sh#n1987
26 > >
27 > > Fabian
28 > >
29 > >
30 > Ah, yes, I missed the part about it being BSD-specific.
31 >
32 > This one-liner certainly isn't as graceful or elegant, but it works:
33 >
34 > # cat /proc/cpuinfo | grep 'processor' | wc -l
35 >
36
37 # grep -c processor /proc/cpuinfo
38
39 however Documentation/filesystems/proc.txt is very vague on it's content,
40 just stating it has info on the cpu, better leave this as a backup value
41 IMHO