From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3vqJFf5ThnzDq95 for ; Fri, 24 Mar 2017 20:36:06 +1100 (AEDT) Received: from pps.filterd (m0098409.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.20/8.16.0.20) with SMTP id v2O9Yd71116018 for ; Fri, 24 Mar 2017 05:36:04 -0400 Received: from e06smtp11.uk.ibm.com (e06smtp11.uk.ibm.com [195.75.94.107]) by mx0a-001b2d01.pphosted.com with ESMTP id 29cm3u0x5e-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Fri, 24 Mar 2017 05:36:04 -0400 Received: from localhost by e06smtp11.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 24 Mar 2017 09:36:00 -0000 Date: Fri, 24 Mar 2017 10:35:55 +0100 From: Heiko Carstens To: Christian Borntraeger Cc: Pavel Tatashin , linux-kernel@vger.kernel.org, sparclinux@vger.kernel.org, linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, linux-s390 Subject: Re: [v1 0/5] parallelized "struct page" zeroing References: <1490310113-824438-1-git-send-email-pasha.tatashin@oracle.com> <341568c3-0473-860f-aa20-63723aa40b87@de.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <341568c3-0473-860f-aa20-63723aa40b87@de.ibm.com> Message-Id: <20170324093555.GB5891@osiris> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Fri, Mar 24, 2017 at 09:51:09AM +0100, Christian Borntraeger wrote: > On 03/24/2017 12:01 AM, 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. > > > > On x86 time saving is going to be even greater (proportionally to memory size) > > because there are twice as many "struct page"es for the same amount of memory, > > as base pages are twice smaller. > > Fixing the linux-s390 mailing list email. > This might be useful for s390 as well. Unfortunately only for the fake numa case, since as far as I understand it, parallelization happens only on a node granularity. And since we are usually only having one node... But anyway, it won't hurt to set ARCH_SUPPORTS_DEFERRED_STRUCT_PAGE_INIT on s390 also. I'll do some testing and then we'll see. Pavel, could you please change your patch 5 so it also converts the s390 call sites of vmemmap_alloc_block() so they use VMEMMAP_ZERO instead of 'true' as argument?