Using all cores with Microsoft R Open and Google Compute Engine

Question

I'm using Microsoft R Open on a GCE instance that has two vCPUs. Here are its specs.

$ lscpu
Architecture:          x86_64
CPU op-mode(s):        32-bit, 64-bit
Byte Order:            Little Endian
CPU(s):                2
On-line CPU(s) list:   0,1
Thread(s) per core:    2
Core(s) per socket:    1
Socket(s):             1
NUMA node(s):          1
Vendor ID:             GenuineIntel
CPU family:            6
Model:                 63
Model name:            Intel(R) Xeon(R) CPU @ 2.30GHz
Stepping:              0
CPU MHz:               2300.000
BogoMIPS:              4600.00
Hypervisor vendor:     KVM
Virtualization type:   full
L1d cache:             32K
L1i cache:             32K
L2 cache:              256K
L3 cache:              46080K
NUMA node0 CPU(s):     0,1
Flags:                 fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush
 mmx fxsr sse sse2 ss ht syscall nx pdpe1gb rdtscp lm constant_tsc rep_good nopl xtopology nonstop_tsc
 eagerfpu pni pclmulqdq ssse3 fma cx16 sse4_1 sse4_2 x2apic movbe popcnt aes xsave avx f16c rdrand hyp
ervisor lahf_lm abm fsgsbase tsc_adjust bmi1 avx2 smep bmi2 erms xsaveopt

Even though I have two cores, Microsoft R Open seems to recognize only one of them, so I'm not taking full advantage of my computing capacity. I can't set the numbers of threads manually either.

Microsoft R Open 3.3.2
The enhanced R distribution from Microsoft
Microsoft packages Copyright (C) 2016 Microsoft Corporation
Using the Intel MKL for parallel mathematical computing(using 1 cores).
Default CRAN mirror snapshot taken on 2016-11-01.
See: https://mran.microsoft.com/.
> getMKLthreads()
[1] 1
> setMKLthreads(2)
Number of threads at maximum: no change has been made.

Here's a graph showing CPU usage. It never uses more than 50% of CPU power.

So, what should I do so I can use all my cores with MRO?

Answer 1

you are running Xeon which is hyper threaded . You have 1 cpu with hyper threading,the os treats it as 2 cpus but there is only one physical cpu. MRO uses the physical cores only(without hyper threading)

Answer 2

You can use this:

library(doParallel)
no_cores <- detectCores() - 1
registerDoParallel(cores=no_cores)

It will one core less than the actual cores you have. It leaves one core for OS operations. Try it out.