Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751135AbWINUZ7 (ORCPT ); Thu, 14 Sep 2006 16:25:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751143AbWINUZ7 (ORCPT ); Thu, 14 Sep 2006 16:25:59 -0400 Received: from dvhart.com ([64.146.134.43]:55265 "EHLO dvhart.com") by vger.kernel.org with ESMTP id S1751135AbWINUZ6 (ORCPT ); Thu, 14 Sep 2006 16:25:58 -0400 Message-ID: <4509BAD4.8010206@mbligh.org> Date: Thu, 14 Sep 2006 13:25:56 -0700 From: Martin Bligh User-Agent: Mozilla Thunderbird 1.0.7 (X11/20051011) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Ingo Molnar Cc: Roman Zippel , Mathieu Desnoyers , linux-kernel@vger.kernel.org, Christoph Hellwig , Andrew Morton , Ingo Molnar , Greg Kroah-Hartman , Thomas Gleixner , Tom Zanussi , ltt-dev@shafik.org, Michel Dagenais Subject: Re: [PATCH 0/11] LTTng-core (basic tracing infrastructure) 0.5.108 References: <20060914033826.GA2194@Krystal> <20060914112718.GA7065@elte.hu> <20060914135548.GA24393@elte.hu> <20060914171320.GB1105@elte.hu> In-Reply-To: <20060914171320.GB1105@elte.hu> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1298 Lines: 32 > if there are lots of tracepoints (and the union of _all_ useful > tracepoints that i ever encountered in my life goes into the thousands) > then the overhead is not zero at all. > > also, the other disadvantages i listed very much count too. Static > tracepoints are fundamentally limited because: > > - they can only be added at the source code level > > - modifying them requires a reboot which is not practical in a > production environment > > - there can only be a limited set of them, while many problems need > finegrained tracepoints tailored to the problem at hand > > - conditional tracepoints are typically either nonexistent or very > limited. > > for me these are all _independent_ grounds for rejection, as a generic > kernel infrastructure. I don't think anyone is saying that static tracepoints do not have their limitations, or that dynamic tracepointing is useless. But that's not the point ... why can't we have one infrastructure that supports both? Preferably in a fairly simple, consistent way. M. - 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/