From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from albireo.enyo.de (albireo.enyo.de [37.24.231.21]) by sourceware.org (Postfix) with ESMTPS id 7B9E4385DC0B; Mon, 4 May 2020 04:36:10 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 7B9E4385DC0B Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=deneb.enyo.de Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=fw@deneb.enyo.de Received: from [172.17.203.2] (helo=deneb.enyo.de) by albireo.enyo.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) id 1jVSps-0003vx-QH; Mon, 04 May 2020 04:36:08 +0000 Received: from fw by deneb.enyo.de with local (Exim 4.92) (envelope-from ) id 1jVSps-00026H-Mc; Mon, 04 May 2020 06:36:08 +0200 From: Florian Weimer To: Norbert Manthey Cc: libc-alpha@sourceware.org, Siddhesh Poyarekar Subject: Re: [[RFC][PATCH] v1 0/2] malloc/realloc with transparent huge page support References: <20200503220708.2048246-1-nmanthey@conp-solutions.com> Date: Mon, 04 May 2020 06:36:08 +0200 In-Reply-To: <20200503220708.2048246-1-nmanthey@conp-solutions.com> (Norbert Manthey's message of "Mon, 4 May 2020 00:07:06 +0200") Message-ID: <87ftcgz58n.fsf@mid.deneb.enyo.de> MIME-Version: 1.0 Content-Type: text/plain X-Spam-Status: No, score=-9.4 required=5.0 tests=BAYES_00, KAM_DMARC_STATUS, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 04 May 2020 04:36:21 -0000 * Norbert Manthey: > This change has been tested on top of glibc 2.23 in an Ubuntu 16.04 > environment for programs that benefit from huge pages due to their > large memory usage and pseudo-random memory access patterns > (e.g. SAT solvers, model checkers, optimization tools an > others). More details on the performance improvements for these > tools can be found in https://arxiv.org/abs/2004.14378, e.g. page 9. Please show us the output of $ cat /sys/kernel/mm/transparent_hugepage/enabled from your test systems. Thanks. In the paper, you say this: | Because there might be applications running on the host that would | suffer from larger pages, THP is usually disabled on physical | systems and it is not advised to set the value to always. However, the default value for Red Hat Enterprise Linux 7 is, in fact, "always", so it is puzzling why you see such a large benefit for long-running processes.