From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f72.google.com (mail-wm0-f72.google.com [74.125.82.72]) by kanga.kvack.org (Postfix) with ESMTP id 09EBF6B002A for ; Thu, 15 Feb 2018 04:02:50 -0500 (EST) Received: by mail-wm0-f72.google.com with SMTP id f15so7600367wmd.1 for ; Thu, 15 Feb 2018 01:02:49 -0800 (PST) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id f28sor7708358edd.4.2018.02.15.01.02.48 for (Google Transport Security); Thu, 15 Feb 2018 01:02:48 -0800 (PST) Date: Thu, 15 Feb 2018 12:02:46 +0300 From: "Kirill A. Shutemov" Subject: Re: [bug?] mallocstress poor performance with THP on arm64 system Message-ID: <20180215090246.qrsnncq3ajtbdlfy@node.shutemov.name> References: <1523287676.1950020.1518648233654.JavaMail.zimbra@redhat.com> <1847959563.1954032.1518649501357.JavaMail.zimbra@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1847959563.1954032.1518649501357.JavaMail.zimbra@redhat.com> Sender: owner-linux-mm@kvack.org List-ID: To: Jan Stancek Cc: linux-mm@kvack.org, lwoodman , Rafael Aquini , Andrea Arcangeli On Wed, Feb 14, 2018 at 06:05:01PM -0500, Jan Stancek wrote: > Hi, > > mallocstress[1] LTP testcase takes ~5+ minutes to complete > on some arm64 systems (e.g. 4 node, 64 CPU, 256GB RAM): > real 7m58.089s > user 0m0.513s > sys 24m27.041s > > But if I turn off THP ("transparent_hugepage=never") it's a lot faster: > real 0m4.185s > user 0m0.298s > sys 0m13.954s > It's multi-threaded workload. My *guess* is that poor performance is due to lack of ARCH_ENABLE_SPLIT_PMD_PTLOCK support on arm64. -- Kirill A. Shutemov -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org