From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 15745 invoked by alias); 25 Oct 2009 02:01:12 -0000 Received: (qmail 15661 invoked by uid 22791); 25 Oct 2009 02:01:11 -0000 X-SWARE-Spam-Status: No, hits=-2.5 required=5.0 tests=AWL,BAYES_00 X-Spam-Check-By: sourceware.org Received: from smtp-outbound-1.vmware.com (HELO smtp-outbound-1.vmware.com) (65.115.85.69) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Sun, 25 Oct 2009 02:01:04 +0000 Received: from mailhost3.vmware.com (mailhost3.vmware.com [10.16.27.45]) by smtp-outbound-1.vmware.com (Postfix) with ESMTP id E33EC13627; Sat, 24 Oct 2009 19:01:02 -0700 (PDT) Received: from [10.20.94.141] (msnyder-server.eng.vmware.com [10.20.94.141]) by mailhost3.vmware.com (Postfix) with ESMTP id D6D67CD9A5; Sat, 24 Oct 2009 19:01:02 -0700 (PDT) Message-ID: <4AE3AFB5.8050809@vmware.com> Date: Sun, 25 Oct 2009 12:57:00 -0000 From: Michael Snyder User-Agent: Thunderbird 1.5.0.12 (X11/20080411) MIME-Version: 1.0 To: Nicholas Mc Guire CC: "y@opentech.at" , martin mangard , "gdb@sourceware.org" Subject: Re: create a watchpoint with trace functionality References: <325d766d0910210158y47944e5es48e44929fddb3770@mail.gmail.com> <4ADF1A75.7040602@vmware.com> <20091021145241.GA11882@opentech.at> In-Reply-To: <20091021145241.GA11882@opentech.at> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-IsSubscribed: yes Mailing-List: contact gdb-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-owner@sourceware.org X-SW-Source: 2009-10/txt/msg00360.txt.bz2 Nicholas Mc Guire wrote: > On Wed, 21 Oct 2009, Michael Snyder wrote: > >> martin mangard wrote: >>> Hello >>> >>> I'm trying to trace the value of a global status variable of an >>> application. This variable is changed from various code positions. I >>> would like to log/trace each change of this variable without stopping >>> the application (at least for a long time) in order to perform a >>> longterm test. I'm currently using a hardware-watchpoint >>> >>> Is there a possibility to configure a "autocontinue" after a >>> watchpoint-event? Which means that the changed value is printed and >>> the execution continues without any user interaction (pressing "c")? >> Yes, sure. See below. >> >>> Is ist possible to set a tracepoint on a change of a memory area? >> A tracepoint is different from a watchpoint, and no, I don't >> remember that you can do that with a tracepoint (I could be >> wrong). > > you are right - no support for that in tracepoints - tracepoints are just > like breakpoints just that they execute the bytecode provided > rather than stoping the process and calling the gdb-frontend. But > I guess that due to the invasive nature of watchpoints (execution timing wise) > it would not make that much sense to have a that behavior in tracepoints as > the prime intention of tracepoints is to allow debugging without breaking > the temporal behoavior too badly (the impact is of course still significant). Hardware watchpoints associated with tracepoints would make sense. Software watchpoints wouldn't. And of course, there are resource limits associated with hardware watchpoints.