From owner-freebsd-performance@FreeBSD.ORG Wed Oct 20 21:08:22 2004 Return-Path: Delivered-To: freebsd-performance@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 4694416A4CE for ; Wed, 20 Oct 2004 21:08:22 +0000 (GMT) Received: from gen129.n001.c02.escapebox.net (gen129.n001.c02.escapebox.net [213.73.91.129]) by mx1.FreeBSD.org (Postfix) with ESMTP id 062DE43D48 for ; Wed, 20 Oct 2004 21:08:22 +0000 (GMT) (envelope-from gemini@geminix.org) Message-ID: <4176D3C3.30007@geminix.org> Date: Wed, 20 Oct 2004 23:08:19 +0200 From: Uwe Doering Organization: Private UNIX Site User-Agent: Mozilla/5.0 (X11; U; FreeBSD i386; en-US; rv:1.7.2) Gecko/20041002 X-Accept-Language: en-us, en MIME-Version: 1.0 To: freebsd-performance@freebsd.org References: <004001c4b69d$80e21f40$0c0210ac@ADMIN1><41766350.4080901@centtech.com> <006001c4b6ad$38a8cac0$0c0210ac@ADMIN1> <4176C7A8.6030407@geminix.org> <006701c4b6e4$ab133d20$b3db87d4@multiplay.co.uk> In-Reply-To: <006701c4b6e4$ab133d20$b3db87d4@multiplay.co.uk> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Received: from gemini by geminix.org with asmtp (TLSv1:AES256-SHA:256) (Exim 3.36 #1) id 1CKNgy-000F7P-00; Wed, 20 Oct 2004 23:08:21 +0200 Subject: Re: decreasing interrupt CPU load X-BeenThere: freebsd-performance@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Performance/tuning List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 20 Oct 2004 21:08:22 -0000 Steven Hartland wrote: >> Since you mentioned earlier that you run this on an SMP system, are >> you aware that device polling is available only for single CPU >> kernels, that is, not in SMP mode? This is poorly documented, >> unfortunately. You can find out about it by looking at the first >> couple of lines of 'sys/kern/kern_poll.c'. > > Actually it does work quite well on an SMP machine if you comment said > lines out :) I wonder, can you define how well "quite well" actually is? I mean, it's of course everyone's own decision, but I wouldn't dare to do this on a production system. Is there a statement on this available from the author of the code? One should think that he must have had a reason for explicitly disabling device polling for SMP. Maybe locking issues (race conditions)? Uwe -- Uwe Doering | EscapeBox - Managed On-Demand UNIX Servers gemini@geminix.org | http://www.escapebox.net