[R-SIG-Mac] detecting cores

Charles DiMaggio charles.dimaggio at gmail.com
Fri Feb 5 13:13:13 CET 2016


Running 10.9.5 on 3.7Ghz Quad-Core:


$ /usr/sbin/sysctl -n hw.physicalcpu
4
$ /usr/sbin/sysctl -n hw.logicalcp
second level name logicalcp in hw.logicalcp is invalid


Charles DiMaggio, PhD, MPH
Professor of Surgery and Population Health
Director of Injury Research
Department of Surgery
New York University School of Medicine






On Feb 5, 2016, at 7:07 AM, Prof Brian Ripley <ripley at stats.ox.ac.uk> wrote:

> sysctl on 10.11 has options which would enable us to differentiate between logical and physical codes on parallel::detectCores --- however these are not documented in Apple's online man pages, which are for 10.9.  Could someone running 10.9 and someone for 10.10 report if
> 
> /usr/sbin/sysctl -n hw.physicalcpu
> /usr/sbin/sysctl -n hw.logicalcpu
> 
> run in a terminal work and gives the correct result?  (Normally the second will be twice the first taking account of hyperthreading.)
> 
> Thanks in advance.
> 
> -- 
> Brian D. Ripley,                  ripley at stats.ox.ac.uk
> Emeritus Professor of Applied Statistics, University of Oxford
> 
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