From mboxrd@z Thu Jan 1 00:00:00 1970 From: zimoun Subject: R, openBlas and max thread? Date: Mon, 18 Feb 2019 16:12:41 +0100 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Return-path: Received: from eggs.gnu.org ([209.51.188.92]:49431) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gvkbL-0006b5-BY for help-guix@gnu.org; Mon, 18 Feb 2019 10:13:00 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gvkbJ-0004LW-UR for help-guix@gnu.org; Mon, 18 Feb 2019 10:12:59 -0500 Received: from mail-qt1-x82a.google.com ([2607:f8b0:4864:20::82a]:40403) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1gvkbJ-0004I3-4G for help-guix@gnu.org; Mon, 18 Feb 2019 10:12:57 -0500 Received: by mail-qt1-x82a.google.com with SMTP id j36so19500431qta.7 for ; Mon, 18 Feb 2019 07:12:53 -0800 (PST) List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: help-guix-bounces+gcggh-help-guix=m.gmane.org@gnu.org Sender: "Help-Guix" To: help-guix 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