Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750705AbWABMp7 (ORCPT ); Mon, 2 Jan 2006 07:45:59 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750707AbWABMp7 (ORCPT ); Mon, 2 Jan 2006 07:45:59 -0500 Received: from mx2.suse.de ([195.135.220.15]:50120 "EHLO mx2.suse.de") by vger.kernel.org with ESMTP id S1750705AbWABMp7 (ORCPT ); Mon, 2 Jan 2006 07:45:59 -0500 From: Andi Kleen To: Pekka Enberg Subject: Re: [POLL] SLAB : Are the 32 and 192 bytes caches really usefull on x86_64 machines ? Date: Mon, 2 Jan 2006 13:45:44 +0100 User-Agent: KMail/1.8.2 Cc: Denis Vlasenko , Eric Dumazet , linux-kernel@vger.kernel.org References: <7vbqzadgmt.fsf@assigned-by-dhcp.cox.net> <3186311.1135792635763.SLOX.WebMail.wwwrun@imap-dhs.suse.de> <84144f020601020037n7af7ac54l74cdbe602372c7f@mail.gmail.com> In-Reply-To: <84144f020601020037n7af7ac54l74cdbe602372c7f@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200601021345.44843.ak@suse.de> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 846 Lines: 21 On Monday 02 January 2006 09:37, Pekka Enberg wrote: > On 12/28/05, Andreas Kleen wrote: > > I remember the original slab paper from Bonwick actually mentioned that > > power of two slabs are the worst choice for a malloc - but for some reason Linux > > chose them anyways. > > Power of two sizes are bad because memory accesses tend to concentrate > on the same cache lines but slab coloring should take care of that. So > I don't think there's a problem with using power of twos for kmalloc() > caches. There is - who tells you it's the best possible distribution of memory? -Andi - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/