From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754080Ab3KAVYB (ORCPT ); Fri, 1 Nov 2013 17:24:01 -0400 Received: from mx1.redhat.com ([209.132.183.28]:64378 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750736Ab3KAVYA (ORCPT ); Fri, 1 Nov 2013 17:24:00 -0400 Message-ID: <52741BE0.4070306@redhat.com> Date: Fri, 01 Nov 2013 17:23:44 -0400 From: Rik van Riel User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130625 Thunderbird/17.0.7 MIME-Version: 1.0 To: Davidlohr Bueso CC: Andrew Morton , Hugh Dickins , Michel Lespinasse , Ingo Molnar , Mel Gorman , Guan Xuetao , aswin@hp.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH] mm: cache largest vma References: <1383337039.2653.18.camel@buesod1.americas.hpqcorp.net> In-Reply-To: <1383337039.2653.18.camel@buesod1.americas.hpqcorp.net> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/01/2013 04:17 PM, Davidlohr Bueso wrote: > While caching the last used vma already does a nice job avoiding > having to iterate the rbtree in find_vma, we can improve. After > studying the hit rate on a load of workloads and environments, > it was seen that it was around 45-50% - constant for a standard > desktop system (gnome3 + evolution + firefox + a few xterms), > and multiple java related workloads (including Hadoop/terasort), > and aim7, which indicates it's better than the 35% value documented > in the code. > > By also caching the largest vma, that is, the one that contains > most addresses, there is a steady 10-15% hit rate gain, putting > it above the 60% region. This improvement comes at a very low I suspect this will especially help when also using automatic numa balancing, which causes periodic page faults. Acked-by: Rik van Riel -- All rights reversed