From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755850Ab1KVOO3 (ORCPT ); Tue, 22 Nov 2011 09:14:29 -0500 Received: from mga14.intel.com ([143.182.124.37]:52485 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750995Ab1KVOO1 (ORCPT ); Tue, 22 Nov 2011 09:14:27 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.69,553,1315206000"; d="scan'208";a="77967280" Date: Tue, 22 Nov 2011 22:14:20 +0800 From: Wu Fengguang To: Andi Kleen Cc: Andrew Morton , Linux Memory Management List , "linux-fsdevel@vger.kernel.org" , Ingo Molnar , Jens Axboe , Peter Zijlstra , Rik van Riel , LKML Subject: Re: [PATCH 5/8] readahead: add /debug/readahead/stats Message-ID: <20111122141420.GA29261@localhost> References: <20111121091819.394895091@intel.com> <20111121093846.636765408@intel.com> <20111121141759.GE24062@one.firstfloor.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20111121141759.GE24062@one.firstfloor.org> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Andi, On Mon, Nov 21, 2011 at 10:17:59PM +0800, Andi Kleen wrote: > > +static unsigned long ra_stats[RA_PATTERN_MAX][RA_ACCOUNT_MAX]; > > Why not make it per cpu? That should get the overhead down, probably > even enough that it can be enabled by default. > > BTW I have an older framework to make it really easy to add per > cpu stats counters to debugfs. Will repost, that would simplify > it even more. That's definitely a good facility to have. I would be happy to become its first user :) Thanks, Fengguang