From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752897Ab3KSU2M (ORCPT ); Tue, 19 Nov 2013 15:28:12 -0500 Received: from userp1040.oracle.com ([156.151.31.81]:22090 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751334Ab3KSU2L (ORCPT ); Tue, 19 Nov 2013 15:28:11 -0500 Message-ID: <528BC9AA.5020300@oracle.com> Date: Tue, 19 Nov 2013 13:27:22 -0700 From: Khalid Aziz Organization: Oracle Corp User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.1.0 MIME-Version: 1.0 To: Andrea Arcangeli , Andrew Morton CC: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Pravin Shelar , Greg Kroah-Hartman , Ben Hutchings , Christoph Lameter , Johannes Weiner , Mel Gorman , Rik van Riel , Andi Kleen , Minchan Kim , Linus Torvalds Subject: Re: [PATCH 0/3] mm: hugetlbfs: fix hugetlbfs optimization v2 References: <1384537668-10283-1-git-send-email-aarcange@redhat.com> <528A56A7.3020301@oracle.com> In-Reply-To: <528A56A7.3020301@oracle.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Source-IP: acsinet22.oracle.com [141.146.126.238] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/18/2013 11:04 AM, Khalid Aziz wrote: > On 11/15/2013 10:47 AM, Andrea Arcangeli wrote: >> Hi, >> >> 1/3 is a bugfix so it should be applied more urgently. 1/3 is not as >> fast as the current upstream code in the hugetlbfs + directio extreme >> 8GB/sec benchmark (but 3/3 should fill the gap later). The code is >> identical to the one I posted in v1 just rebased on upstream and was >> developed in collaboration with Khalid who already tested it. >> >> 2/3 and 3/3 had very little testing yet, and they're incremental >> optimization. 2/3 is minor and most certainly worth applying later. >> >> 3/3 instead complicates things a bit and adds more branches to the THP >> fast paths, so it should only be applied if the benchmarks of >> hugetlbfs + directio show that it is very worthwhile (that has not >> been verified yet). If it's not worthwhile 3/3 should be dropped (and >> the gap should be filled in some other way if the gap is not caused by >> the _mapcount mangling as I guessed). Ideally this should bring even >> more performance than current upstream code, as current upstream code >> still increased the _mapcount in gup_fast by mistake, while this >> eliminates the locked op on the tail page cacheline in gup_fast too >> (which is required for correctness too). > > Hi Andrea, > > I ran directio benchmark and here are the performance numbers (MBytes/sec): > > Block size 3.12 3.12+patch 1 3.12+patch 1,2,3 > ---------- ---- ------------ ---------------- > 1M 8467 8114 7648 > 64K 4049 4043 4175 > > Performance numbers with 64K reads look good but there is further > deterioration with 1M reads. > > -- > Khalid Hi Andrea, I found that a background task running on my test server had influenced the performance numbers for 1M reads. I cleaned that problem up and re-ran the test. I am seeing 8456 MB/sec with all three patches applied, so 1M number is looking good as well. -- Khalid