Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763864AbYARXVR (ORCPT ); Fri, 18 Jan 2008 18:21:17 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754338AbYARXVH (ORCPT ); Fri, 18 Jan 2008 18:21:07 -0500 Received: from mga07.intel.com ([143.182.124.22]:64447 "EHLO azsmga101.ch.intel.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751933AbYARXVF (ORCPT ); Fri, 18 Jan 2008 18:21:05 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.25,218,1199692800"; d="scan'208";a="368980721" Message-ID: <47913435.4010004@linux.intel.com> Date: Fri, 18 Jan 2008 15:20:21 -0800 From: Arjan van de Ven User-Agent: Thunderbird 1.5.0.14 (Windows/20071210) MIME-Version: 1.0 To: "Frank Ch. Eigler" CC: Arjan van de Ven , Linux Kernel Mailing List , Linus Torvalds , Ingo Molnar , Andrew Morton Subject: Re: [patch 2/3] Latencytop instrumentations part 1 References: <4790E3A6.7060807@linux.intel.com> <20080118094048.10e79ff9@laptopd505.fenrus.org> <20080118143334.28ba08ca@laptopd505.fenrus.org> <20080118231109.GC27193@redhat.com> In-Reply-To: <20080118231109.GC27193@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1337 Lines: 28 Frank Ch. Eigler wrote: > Hi - > > On Fri, Jan 18, 2008 at 02:33:34PM -0800, Arjan van de Ven wrote: >> [...] >>> Can you suggest of some reason why all this instrumentation could >>> not be in the form of standard markers (perhaps conditionally >>> compiled out if necessary)? >> sure. Every instrumentation you see is of the nested kind (since the lowest level >> of nesting is already automatic via wchan). >> If markers can provide me the following semantics, I'd be MORE than happy to use markers: >> [...] >> If markers can provide that semantics ... you sold me. > > Further to what acme said, markers are semantics-free. Callback > functions that implement your entry & exit semantics can be attached > at run time, at your pleasure. (So can systemtap probes, for that > matter.) The main difference would be that these callback functions > would have manage the per-thread LIFO data structures themselves, > instead of allocating backpointers on the kernel stack. (Bonus marks > for not modifying task_struct. :-) modifying task struct to have storage space is no big deal... -- 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/