From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e32.co.us.ibm.com (e32.co.us.ibm.com [32.97.110.150]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e32.co.us.ibm.com", Issuer "Equifax" (verified OK)) by ozlabs.org (Postfix) with ESMTP id 97007DDEC9 for ; Tue, 10 Jul 2007 05:56:31 +1000 (EST) Received: from d03relay04.boulder.ibm.com (d03relay04.boulder.ibm.com [9.17.195.106]) by e32.co.us.ibm.com (8.12.11.20060308/8.13.8) with ESMTP id l69Jp3JI030107 for ; Mon, 9 Jul 2007 15:51:03 -0400 Received: from d03av02.boulder.ibm.com (d03av02.boulder.ibm.com [9.17.195.168]) by d03relay04.boulder.ibm.com (8.13.8/8.13.8/NCO v8.3) with ESMTP id l69JuOSA207300 for ; Mon, 9 Jul 2007 13:56:25 -0600 Received: from d03av02.boulder.ibm.com (loopback [127.0.0.1]) by d03av02.boulder.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id l69JuOSg008022 for ; Mon, 9 Jul 2007 13:56:24 -0600 Date: Mon, 9 Jul 2007 14:56:23 -0500 To: Marc Leeman Subject: Re: 2.4/2.6/ppc/powerpc/8245/8347e Message-ID: <20070709195623.GK4457@austin.ibm.com> References: <20070621141519.GQ5417@chiana.homelinux.org> <0090CCD0-EBB4-4475-BF03-36AF41E2DDA1@kernel.crashing.org> <20070621155616.GR5417@chiana.homelinux.org> <20070621171340.GS5417@chiana.homelinux.org> <20070628180632.GA2660@chiana.homelinux.org> <20070629145936.GL2660@chiana.homelinux.org> <20070709154723.GD2660@chiana.homelinux.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20070709154723.GD2660@chiana.homelinux.org> From: linas@austin.ibm.com (Linas Vepstas) Cc: linuxppc-dev@ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Mon, Jul 09, 2007 at 05:47:23PM +0200, Marc Leeman wrote: > > Disabling this replaces the advanced SLAB allocator and > kmalloc support with the drastically simpler SLOB allocator. > SLOB is more space efficient but does not scale well and is > more susceptible to fragmentation. > -------- > > I was expecting a lower DMM performance but wasn't expecting such a > drain on kernel/network load. OK, to be clear: you seem to be saying that using the SLOB instead of the SLAB allocator results in such terrible memory fragmentation that network performance is degraded by large factors (2x or 5x or something like that, if I remember your earlier emails). Is that right? I thought I heard about some memory-defrag patches being posted. What happens if these are used together with SLOB? Does one regain the lost performance? Perhaps maybe one gets even better performance? --linas