Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S267737AbUJOM2G (ORCPT ); Fri, 15 Oct 2004 08:28:06 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S267739AbUJOM2G (ORCPT ); Fri, 15 Oct 2004 08:28:06 -0400 Received: from igw2.watson.ibm.com ([129.34.20.6]:31379 "EHLO igw2.watson.ibm.com") by vger.kernel.org with ESMTP id S267737AbUJOM2B (ORCPT ); Fri, 15 Oct 2004 08:28:01 -0400 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Date: Fri, 15 Oct 2004 08:27:10 -0400 (EDT) To: Lee Revell Cc: Robert Wisniewski , Roland Dreier , karim@opersys.com, Ingo Molnar , linux-kernel , Thomas Zanussi , Richard J Moore , Michel Dagenais Subject: Re: [patch] Real-Time Preemption, -VP-2.6.9-rc4-mm1-U0 In-Reply-To: <1097806897.2682.80.camel@krustophenia.net> References: <20041011215909.GA20686@elte.hu> <20041012091501.GA18562@elte.hu> <20041012123318.GA2102@elte.hu> <20041012195424.GA3961@elte.hu> <20041013061518.GA1083@elte.hu> <20041014002433.GA19399@elte.hu> <416F0071.3040304@opersys.com> <20041014234603.GA22964@elte.hu> <416F14B4.8070002@opersys.com> <52u0swddpk.fsf@topspin.com> <16751.12005.419748.661651@kix.watson.ibm.com> <1097806897.2682.80.camel@krustophenia.net> X-Mailer: VM 6.43 under 20.4 "Emerald" XEmacs Lucid Message-ID: <16751.49412.433407.262686@kix.watson.ibm.com> From: Robert Wisniewski Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1452 Lines: 34 Lee Revell writes: > On Thu, 2004-10-14 at 22:00, Robert Wisniewski wrote: > > Theoretically a problem, in practice not, i.e., good enough for soft/normal > > real-time, not hard real-time; probably wouldn't want my heart monitor on > > it, but then I wouldn't be using Linux for that either :-) > > Also, the issue here is how we do debug logging. You would presumably > not use this at all in production. > > Lee Yes actually you would. If the tracing subsystem is designed correctly you leave it in for production systems and enable it when you need to find a problem. The reason is because many times you can not reproduce a problem someone in production is seeing in your environment. In addition to the LTT/Relayfs and K42 tracing work, lots of of tracing work/papers suggest leaving it in all the time. Most commercial operating systems have made the investment to correctly design tracing facilities so they are available. LTT in combination with relayfs could fulfill that role for Linux. Robert Wisniewski The K42 MP OS Project Advanced Operating Systems Scalable Parallel Systems IBM T.J. Watson Research Center 914-945-3181 http://www.research.ibm.com/K42/ bob@watson.ibm.com - 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/