From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from postout1.mail.lrz.de (postout1.mail.lrz.de [IPv6:2001:4ca0:0:103::81bb:ff89]) by sourceware.org (Postfix) with ESMTPS id 20AE4385840B for ; Mon, 29 Nov 2021 14:56:27 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 20AE4385840B Received: from lxmhs51.srv.lrz.de (localhost [127.0.0.1]) by postout1.mail.lrz.de (Postfix) with ESMTP id 4J2pMX4BrCzyT3 for ; Mon, 29 Nov 2021 15:56:24 +0100 (CET) X-Virus-Scanned: by amavisd-new at lrz.de in lxmhs51.srv.lrz.de X-Spam-Score: -2.879 X-Spam-Level: X-Spam-Status: No, score=0.9 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, RCVD_IN_BARRACUDACENTRAL, SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.4 Received: from postout1.mail.lrz.de ([127.0.0.1]) by lxmhs51.srv.lrz.de (lxmhs51.srv.lrz.de [127.0.0.1]) (amavisd-new, port 20024) with LMTP id eXWr_Mrk0CHZ for ; Mon, 29 Nov 2021 15:56:24 +0100 (CET) Received: from r2-d2.localdomain (dynamic-077-007-049-215.77.7.pool.telefonica.de [77.7.49.215]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (Client did not present a certificate) by postout1.mail.lrz.de (Postfix) with ESMTPSA id 4J2pMW6JwQzySs for ; Mon, 29 Nov 2021 15:56:23 +0100 (CET) Date: Mon, 29 Nov 2021 15:55:31 +0100 From: Andrei Rabusov To: libstdc++@gcc.gnu.org Subject: std::reduce: set max number of threads Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: libstdc++@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libstdc++ mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 29 Nov 2021 14:56:29 -0000 Dear libstdc++ experts, I was searching how to limit the std::reduce function (or similar std::transform_reduce) with a certain number of threads lower then the number of available hardware cores. If I understand docs correctly, there is no such feature in the STL at least according to cppreference, but it would be quite nice to have it at some point. Could you please advise me whom to contact and discuss if it is necessary or possible to implement such a feature? Can it be done by your group as a non standard extension? Best regards Andrei