From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 5197 invoked by alias); 8 Sep 2009 12:08:28 -0000 Received: (qmail 5162 invoked by uid 22791); 8 Sep 2009 12:08:27 -0000 X-SWARE-Spam-Status: No, hits=-2.5 required=5.0 tests=AWL,BAYES_00 X-Spam-Check-By: sourceware.org Received: from smarthost02.mail.zen.net.uk (HELO smarthost02.mail.zen.net.uk) (212.23.3.141) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Tue, 08 Sep 2009 12:08:18 +0000 Received: from [82.69.137.158] (helo=[10.17.20.102]) by smarthost02.mail.zen.net.uk with esmtp (Exim 4.63) (envelope-from ) id 1MkzUa-0006K0-U6; Tue, 08 Sep 2009 12:08:13 +0000 Message-ID: <4AA64929.1040305@undo-software.com> Date: Tue, 08 Sep 2009 12:08:00 -0000 From: Greg Law User-Agent: Thunderbird 2.0.0.21 (X11/20090320) MIME-Version: 1.0 To: Jakob Engblom CC: 'Michael Snyder' , gdb@sourceware.org, 'Julian Smith' Subject: Re: Simics & reverse execution References: <002001ca1f0e$4c9b74a0$e5d25de0$@com> <002101ca1f2e$746e1ad0$5d4a5070$@com> <200908171251.07179.pedro@codesourcery.com> <4A899E2E.6080203@vmware.com> <00b801ca1f74$e5610a90$b0231fb0$@com> <4A89B7E4.9010804@vmware.com> <027701ca209f$64c71ce0$2e5556a0$@com> <4A95E319.6020300@vmware.com> <4A97B9C9.8070501@greglaw.net> <010b01ca2a3c$7766ca70$66345f50$@com> <4A9BF84F.3070404@undo-software.com> <025201ca2ace$a9256430$fb702c90$@com> <4A9D2650.6080209@undo-software.com> <019501ca2ccb$0bc1bd70$23453850$@com> <4AA10B93.4000905@undo-software.com> <005201ca2f8b$23c4cc60$6b4e6520$@com> <4AA4C0A4.7000509@undo-software.com> <009b01ca2f94$9d6508b0$d82f1a10$@com> <4AA4F724.1050708@undo-software.com> <017001ca3054$f2d26020$d8772060$@com> In-Reply-To: <017001ca3054$f2d26020$d8772060$@com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Originating-Smarthost02-IP: [82.69.137.158] 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: 2009-09/txt/msg00132.txt.bz2 Jakob Engblom wrote: > [...] > > The problem is that different backends have different natural semantics here. > > A simulator has a natural semantic of synchronous stop across all processors, > devices, and everything else going on. A hardware across JTAG is far more > likely to stop just a few cores and keep the rest running. Hardware with > recording: ???? > > That's why an abstract bookmark concept is so appealing: it can hide anything in > the backend, and let it worry about setting up times on multiple processors, > multiple machines, or hardware recorders. Ok, yes, I see what you're getting at here: bookmarks might be more easily implemented in some targets than some global linear notion of time. > >> Again, you could go a lot further than I'm proposing right now. But >> that's not to say you need to for this stuff be useful. > > Yes, for us, a 64-bit integer count of time would be quite useful as a general > tool. Cool - so is the general agreement that a scalar notion of time is a useful thing to add, even if it's not supported in all reversible targets? (And bookmarks is an (at least) equally useful notion.) Greg -- Greg Law, Undo Software http://undo-software.com/