From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f200.google.com (mail-pf0-f200.google.com [209.85.192.200]) by kanga.kvack.org (Postfix) with ESMTP id 87EFB6B0333 for ; Thu, 23 Mar 2017 19:26:41 -0400 (EDT) Received: by mail-pf0-f200.google.com with SMTP id p189so334758528pfp.5 for ; Thu, 23 Mar 2017 16:26:41 -0700 (PDT) Received: from bombadil.infradead.org (bombadil.infradead.org. [65.50.211.133]) by mx.google.com with ESMTPS id i1si321224pgn.203.2017.03.23.16.26.40 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 23 Mar 2017 16:26:40 -0700 (PDT) Date: Thu, 23 Mar 2017 16:26:38 -0700 From: Matthew Wilcox Subject: Re: [v1 0/5] parallelized "struct page" zeroing Message-ID: <20170323232638.GB29134@bombadil.infradead.org> References: <1490310113-824438-1-git-send-email-pasha.tatashin@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1490310113-824438-1-git-send-email-pasha.tatashin@oracle.com> Sender: owner-linux-mm@kvack.org List-ID: To: Pavel Tatashin Cc: linux-kernel@vger.kernel.org, sparclinux@vger.kernel.org, linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.or On Thu, Mar 23, 2017 at 07:01:48PM -0400, Pavel Tatashin wrote: > When deferred struct page initialization feature is enabled, we get a > performance gain of initializing vmemmap in parallel after other CPUs are > started. However, we still zero the memory for vmemmap using one boot CPU. > This patch-set fixes the memset-zeroing limitation by deferring it as well. > > Here is example performance gain on SPARC with 32T: > base > https://hastebin.com/ozanelatat.go > > fix > https://hastebin.com/utonawukof.go > > As you can see without the fix it takes: 97.89s to boot > With the fix it takes: 46.91 to boot. How long does it take if we just don't zero this memory at all? We seem to be initialising most of struct page in __init_single_page(), so it seems like a lot of additional complexity to conditionally zero the rest of struct page. -- 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