[R] How to verify R is running with multi-threads

Jong yyalli at gmail.com
Wed Feb 18 23:00:30 CET 2009

Hi all,

I've compiled R (version 2.8.1) from the source code with "--with-
blas=" option in order to use external multi-threaded blas package.
However, it's very hard to verify that compilation is correct and R is
using multi-threads correctly or not. Which command or operation in R
will run with multi-threads?

I assumed that matrix multiplication %*% may call multi-threaded blas
operation. So, I run the following code:

n <- 2000
T = matrix(runif(n*n), nrow=n, ncol=n)
system.time(T %*% T)

and watch R process by using unix top command with show-all-threads
option. However, it seems like my R doesn't use multi-threads but just
run with single thread. Is there any other command that I can use to
verify multi-threads use?

Regarding the with-blas option, I have tried to use either atlas or
gotoblas with the following configure option:
--with-blas="-lptf77blas -lpthread -latlas"
--with-blas="-lgotocblas -lgotoblas -lpthread"

Not sure if my options are correct or not.

Thank you for your and comment or advice in advance.


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