From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 29788 invoked by alias); 7 Aug 2002 15:01:35 -0000 Mailing-List: contact gdb-help@sources.redhat.com; run by ezmlm Precedence: bulk List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-owner@sources.redhat.com Received: (qmail 29781 invoked from network); 7 Aug 2002 15:01:34 -0000 Received: from unknown (HELO crack.them.org) (65.125.64.184) by sources.redhat.com with SMTP; 7 Aug 2002 15:01:34 -0000 Received: from dsl254-114-118.nyc1.dsl.speakeasy.net ([216.254.114.118] helo=nevyn.them.org ident=mail) by crack.them.org with asmtp (Exim 3.12 #1 (Debian)) id 17cSJa-00056b-00; Wed, 07 Aug 2002 10:01:34 -0500 Received: from drow by nevyn.them.org with local (Exim 3.35 #1 (Debian)) id 17cSJq-00012a-00; Wed, 07 Aug 2002 11:01:50 -0400 Date: Wed, 07 Aug 2002 08:01:00 -0000 From: Daniel Jacobowitz To: "William A. Gatliff" Cc: Eli Zaretskii , gdb@sources.redhat.com Subject: Re: using tracepoints function with both host and target on same computer Message-ID: <20020807150150.GA3872@nevyn.them.org> Mail-Followup-To: "William A. Gatliff" , Eli Zaretskii , gdb@sources.redhat.com References: <20020806215201.GA5715@nevyn.them.org> <20020807095153.A5941@saturn.billgatliff.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20020807095153.A5941@saturn.billgatliff.com> User-Agent: Mutt/1.5.1i X-SW-Source: 2002-08/txt/msg00052.txt.bz2 On Wed, Aug 07, 2002 at 09:51:53AM -0500, William A. Gatliff wrote: > Eli: > > > > IMHO, tracepoints should really become part of GDB itself, even for > > native debugging. That would allow us to debug programs where timing is > > critical, such as real-time software, Emacs display engine, etc. I miss > > that feature a lot. > > Wouldn't some kind of stub be present in these situations anyway? So > it'd still be an implementation concern for the stub... > > In fact, I don't see how you could do tracepoints effectively in > anything resembling real time without stub assistance. You don't do them in actual realtime, but neither do you wait for all of GDB to process the event; you receive the breakpoint, collect tracepoint data, and immediately resume without touching GDB's event loop. It's a little slower than an in-application stub because it has to use ptrace to read memory/registers, but not substantially slower. If you need better, you have to link a stub into the application. I think we've been investigating a library for that, but I don't know when/if it'll be available. -- Daniel Jacobowitz Carnegie Mellon University MontaVista Software Debian GNU/Linux Developer