GNU bug report logs - #42044
nproc says "1" on mobile processors

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From: Adam Borowski <kilobyte <at> angband.pl>
To: Pádraig Brady <P <at> draigBrady.com>
Cc: 42044 <at> debbugs.gnu.org
Subject: bug#42044: nproc says "1" on mobile processors
Date: Fri, 26 Jun 2020 21:18:57 +0200

On Fri, Jun 26, 2020 at 07:26:16PM +0100, Pádraig Brady wrote:
> On 25/06/2020 18:37, Adam Borowski wrote:
> > Hi!
> > I'm afraid that `nproc` shows only the number of _currently_ online CPUs,
> > which on mobile processors tends to be 1 when starting a job.  As there's
> > a need to conserve power, holding cores online when they have nothing to
> > do would be a waste, thus they constantly get onlined and offlined.

> > Ie, could you please make nproc include all available CPUs rather than
> > only online ones?
> 
> Does `nproc --all` suffice for your use case?

It works on the mobile box, but doesn't obey affinity mask anymore:

[~]$ numactl -N 0 nproc --all
64
[~]$ numactl -N 0 nproc 
16

I'd wish for fitting all uses, big and small.  Ie, the answer "on this
machine, with currently imposed limits, what's the fastest level of
parallelism?".


Meow.
-- 
⢀⣴⠾⠻⢶⣦⠀
⣾⠁⢠⠒⠀⣿⡁ in the beginning was the boot and root floppies and they were good.
⢿⡄⠘⠷⠚⠋⠀                                       -- <willmore> on #linux-sunxi
⠈⠳⣄⠀⠀⠀⠀

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