Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1766753AbXEBQyJ (ORCPT ); Wed, 2 May 2007 12:54:09 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1766755AbXEBQyJ (ORCPT ); Wed, 2 May 2007 12:54:09 -0400 Received: from wr-out-0506.google.com ([64.233.184.239]:65468 "EHLO wr-out-0506.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1766753AbXEBQyG (ORCPT ); Wed, 2 May 2007 12:54:06 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:sender:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references:x-google-sender-auth; b=p503SkI74gzKzzBE1QVVD95MyV4kVfepTaCQhSq83sIViWlOplabKb5IYwqjBenIq+byYLSYap9qfYFdW+XGYZHZ4l9TgMdXmAYA+aN/PT/UddNYPRuKi75SGGv0wPrQzDinEZOaQng6TxBiGpLLLb/ysgCJ3AcEni+2R4GroKc= Message-ID: <12c511ca0705020954q1230ae85o9ab7ca609fd07507@mail.gmail.com> Date: Wed, 2 May 2007 09:54:04 -0700 From: "Tony Luck" To: "Daniel J Blueman" Subject: Re: Kernel Scalability Cc: "Rajib Majumder" , "Linux Kernel" In-Reply-To: <6278d2220705020843l718b3272k5d6ebf8b827d0806@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <6278d2220705020843l718b3272k5d6ebf8b827d0806@mail.gmail.com> X-Google-Sender-Auth: bf344136d606dec7 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1648 Lines: 34 On 5/2/07, Daniel J Blueman wrote: > > There are 128-processor IA64 systems which run recent 2.6 kernels out > there; the per-processor counters, RCU and page-fault scalability work > has been instrumental to the necessary scaling for decent resource > usage on these. 128 cpu is a bit dated ... there are 512 and 1024 cpu systems being used in production environments. The highest reported count stands at 4096 ... but that was only a prototype system, not a production machine ... a small number of patches were needed to boot (e.g. with 10 kernel daemons per cpu, a default kernel hits the maximum number of process ids limit!). The question of how well it scales is very workload dependent. Most of those high cpu count systems are running scientific workloads that crunch numbers in user mode for 7.5 million years before making a single syscall to print that the answer is 42. Obviously scaling of such applications is near linear. But your original question was about 4-8 cpus with 2.4/2.6 ... you will almost certainly be a lot happier with a recent 2.6 kernel. A great deal of work has been done to make it scale well. But there are still some dark corners that haven't been cleaned up so you will have to run your target application and make your own measurments on scaling. If you find that it doesn't scale well, then we'd like to hear about it here. -Tony - 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/