From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pb0-f53.google.com (mail-pb0-f53.google.com [209.85.160.53]) by kanga.kvack.org (Postfix) with ESMTP id 669E26B0031 for ; Mon, 18 Nov 2013 13:04:51 -0500 (EST) Received: by mail-pb0-f53.google.com with SMTP id ma3so7012249pbc.26 for ; Mon, 18 Nov 2013 10:04:51 -0800 (PST) Received: from psmtp.com ([74.125.245.175]) by mx.google.com with SMTP id mj9si4327887pab.161.2013.11.18.10.04.49 for ; Mon, 18 Nov 2013 10:04:50 -0800 (PST) Message-ID: <528A56A7.3020301@oracle.com> Date: Mon, 18 Nov 2013 11:04:23 -0700 From: Khalid Aziz MIME-Version: 1.0 Subject: Re: [PATCH 0/3] mm: hugetlbfs: fix hugetlbfs optimization v2 References: <1384537668-10283-1-git-send-email-aarcange@redhat.com> In-Reply-To: <1384537668-10283-1-git-send-email-aarcange@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: 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 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 -- 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