From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6A1BDC47258 for ; Mon, 4 May 2020 23:44:40 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 10FA120663 for ; Mon, 4 May 2020 23:44:39 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 10FA120663 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=joshtriplett.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 913368E0089; Mon, 4 May 2020 19:44:38 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 8C4988E0058; Mon, 4 May 2020 19:44:38 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7DAD48E0089; Mon, 4 May 2020 19:44:38 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0147.hostedemail.com [216.40.44.147]) by kanga.kvack.org (Postfix) with ESMTP id 649978E0058 for ; Mon, 4 May 2020 19:44:38 -0400 (EDT) Received: from smtpin29.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 205013AB6 for ; Mon, 4 May 2020 23:44:38 +0000 (UTC) X-FDA: 76780668636.29.love43_7fb6fe4c5c660 X-HE-Tag: love43_7fb6fe4c5c660 X-Filterd-Recvd-Size: 3044 Received: from relay10.mail.gandi.net (relay10.mail.gandi.net [217.70.178.230]) by imf40.hostedemail.com (Postfix) with ESMTP for ; Mon, 4 May 2020 23:44:37 +0000 (UTC) Received: from [192.168.1.4] (50-39-163-217.bvtn.or.frontiernet.net [50.39.163.217]) (Authenticated sender: josh@joshtriplett.org) by relay10.mail.gandi.net (Postfix) with ESMTPSA id 23895240008; Mon, 4 May 2020 23:44:28 +0000 (UTC) Date: Mon, 04 May 2020 16:38:03 -0700 In-Reply-To: References: <20200430201125.532129-1-daniel.m.jordan@oracle.com> <20200430201125.532129-7-daniel.m.jordan@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [PATCH 6/7] mm: parallelize deferred_init_memmap() To: Alexander Duyck ,Daniel Jordan CC: Andrew Morton ,Herbert Xu ,Steffen Klassert ,Alex Williamson ,Alexander Duyck ,Dan Williams ,Dave Hansen ,David Hildenbrand ,Jason Gunthorpe ,Jonathan Corbet ,Kirill Tkhai ,Michal Hocko ,Pavel Machek ,Pavel Tatashin ,Peter Zijlstra ,Randy Dunlap ,Shile Zhang ,Tejun Heo ,Zi Yan ,linux-crypto@vger.kernel.org,linux-mm ,LKML From: Josh Triplett Message-ID: <3C3C62BE-6363-41C3-834C-C3124EB3FFAB@joshtriplett.org> X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On May 4, 2020 3:33:58 PM PDT, Alexander Duyck wrote: >On Thu, Apr 30, 2020 at 1:12 PM Daniel Jordan > wrote: >> /* >> - * Initialize and free pages in MAX_ORDER sized increments so >> - * that we can avoid introducing any issues with the buddy >> - * allocator=2E >> + * More CPUs always led to greater speedups on tested >systems, up to >> + * all the nodes' CPUs=2E Use all since the system is >otherwise idle now=2E >> */ > >I would be curious about your data=2E That isn't what I have seen in the >past=2E Typically only up to about 8 or 10 CPUs gives you any benefit, >beyond that I was usually cache/memory bandwidth bound=2E I've found pretty much linear performance up to memory bandwidth, and on t= he systems I was testing, I didn't saturate memory bandwidth until about th= e full number of physical cores=2E From number of cores up to number of thr= eads, the performance stayed about flat; it didn't get any better or worse= =2E - Josh