R, openBlas and max thread?

[zimoun]

Dear,

I am not sure to understand if it is expected or not.

Let install R, guix package -i r, and then run the small script:

> N <- 9000;A <- array(0.1, dim=c(N,N));B <- array(0.1, dim=c(N,N))
> dim(B %*% A)

Monitoring with htop, only 8 of my 16 cores are used. Why ?
And if I have more, then again only 8 cores will be used.

Is it from OpenBlas?
I miss the compilation option forcing this behaviour. I expect that R
will use as many core as available. Right?


Thank you for any insight.

All the best,
simon