Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754367AbZDGAei (ORCPT ); Mon, 6 Apr 2009 20:34:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752040AbZDGAe3 (ORCPT ); Mon, 6 Apr 2009 20:34:29 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.123]:61160 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751471AbZDGAe2 (ORCPT ); Mon, 6 Apr 2009 20:34:28 -0400 Date: Mon, 6 Apr 2009 20:34:20 -0400 (EDT) From: Steven Rostedt X-X-Sender: rostedt@gandalf.stny.rr.com To: "Paul E. McKenney" cc: Frederic Weisbecker , Tom Zanussi , Ingo Molnar , linux-kernel Subject: Re: [PATCH] tracing/filters: allow event filters to be set only when not tracing In-Reply-To: <20090406235850.GA20273@linux.vnet.ibm.com> Message-ID: References: <1238830355.22495.55.camel@bookworm> <1238916865.7989.212.camel@tropicana> <20090405171146.GK6893@linux.vnet.ibm.com> <20090406161527.GD6988@linux.vnet.ibm.com> <20090406194417.GA5936@nowhere> <20090406201524.GF6988@linux.vnet.ibm.com> <20090406235850.GA20273@linux.vnet.ibm.com> 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: 1069 Lines: 30 On Mon, 6 Apr 2009, Paul E. McKenney wrote: > > Hmmm... Do the start_critical_timings() and stop_critical_timings() > functions have anything to do with ftrace()? Yep. > > It does not look like I can just bury RCU-idle controls in these > functions, given that they are also invoked around call_console_drivers(), > but if all the idle loops are surrounded by stop_critical_timings() and > start_critical_timings(), that would ease location of all the idle > loops. ;-) They are for the irqsoff tracer. Several archs will disable interrupts and call an assembly "halt" type instruction that can be woken up by interrupts. But this skips the irqs off check, and we end up with irqsoff showing the idle loop with huge interrupts off latencies. I'm not sure they are included in all archs. They may be. -- 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/