[Rd] R process (and forked children via system2) are limited to 1 core?
Tom Kraljevic
tomk at 0xdata.com
Tue Aug 5 04:49:04 CEST 2014
Hi,
(Using R 3.1.1 on Ubuntu 12.04.4 LTS)
What is the recommended way for R to fork a (non-R) process that is not CPU limited?
Currently I am using R’s system2() call, and this is inheriting the environment of the R process.
I notice that (at least on Linux) when I am poking around /proc that the R process itself is setting up cpu limitations for itself (max 1 core).
Using strace, I see the following:
(strace output)
out.20612:sched_setaffinity(0, 128, {100, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}) = 0
And proc shows:
(cat /proc/nnn/status)
Cpus_allowed: 00000001
Cpus_allowed_list: 0
See that the Cpus_allowed bitmask is a single core. Normally it’s fff…f.
I want my child process (java in this case) not to share this limitation. What is the recommended way of doing this from R?
Any ideas or suggestions appreciated!
Thanks,
Tom
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