Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757555AbZGHVRK (ORCPT ); Wed, 8 Jul 2009 17:17:10 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755019AbZGHVRD (ORCPT ); Wed, 8 Jul 2009 17:17:03 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.123]:51565 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755328AbZGHVRD (ORCPT ); Wed, 8 Jul 2009 17:17:03 -0400 Date: Wed, 8 Jul 2009 17:16:59 -0400 (EDT) From: Steven Rostedt X-X-Sender: rostedt@gandalf.stny.rr.com To: Mathieu Desnoyers cc: linux-kernel@vger.kernel.org, Ingo Molnar , Andrew Morton , Thomas Gleixner , Peter Zijlstra , Frederic Weisbecker , Steven Rostedt , "Paul E. McKenney" Subject: Re: [PATCH 2/3] ring-buffer: make lockless In-Reply-To: <20090708210522.GA17430@Krystal> Message-ID: References: <20090708201312.222046866@goodmis.org> <20090708201445.696220393@goodmis.org> <20090708210522.GA17430@Krystal> User-Agent: Alpine 2.00 (DEB 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1419 Lines: 35 On Wed, 8 Jul 2009, Mathieu Desnoyers wrote: > * Steven Rostedt (rostedt@goodmis.org) wrote: > > From: Steven Rostedt > > > > This patch converts the ring buffers into a completely lockless > > buffer recording system. The read side still takes locks since > > we still serialize readers. But the writers are the ones that > > must be lockless (those can happen in NMIs). > > Hi Steven, > > Have you started modeling this scheme with Promela as I previously > discussed with you ? Paul McKenney did a lot of nice papers on the > topic, and given the complexity level of this lockless buffering > algorithm, I'd be much more comfortable if it was formally verified. The > idea here is to make sure we don't start an endless bug-chasing hunt as > trace buffers gets more exposure to various workloads. I would when I get time. Too many things on my plate at the moment. But I do constantly run my ring-buffer-benchmark module, which highly stresses the buffer. I have not had to fix a bug in it for a long time, and nothing that needed a design change. I'll try it out (or better yet, maybe someone else will) when I get more time. -- Steve -- 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/