From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 27752 invoked by alias); 20 Dec 2012 11:43:20 -0000 Received: (qmail 27744 invoked by uid 22791); 20 Dec 2012 11:43:19 -0000 X-SWARE-Spam-Status: No, hits=-6.2 required=5.0 tests=AWL,BAYES_00,KHOP_RCVD_UNTRUST,RCVD_IN_DNSWL_HI,SPF_HELO_PASS,T_RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Thu, 20 Dec 2012 11:43:10 +0000 Received: from int-mx02.intmail.prod.int.phx2.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id qBKBh6UR014742 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Thu, 20 Dec 2012 06:43:06 -0500 Received: from host2.jankratochvil.net (ovpn-116-39.ams2.redhat.com [10.36.116.39]) by int-mx02.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id qBKBTuiA020415 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES128-SHA bits=128 verify=NO); Thu, 20 Dec 2012 06:30:01 -0500 Date: Thu, 20 Dec 2012 11:43:00 -0000 From: Jan Kratochvil To: "Metzger, Markus T" Cc: "palves@redhat.com" , "tromey@redhat.com" , "kettenis@gnu.org" , "gdb-patches@sourceware.org" , "markus.t.metzger@gmail.com" Subject: Re: [patch v6 00/12] branch tracing support for Atom Message-ID: <20121220112955.GA1420@host2.jankratochvil.net> References: <1355760101-26237-1-git-send-email-markus.t.metzger@intel.com> <20121218091953.GF8054@host2.jankratochvil.net> <20121218135437.GA16636@host2.jankratochvil.net> <20121220071726.GA26625@host2.jankratochvil.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) X-IsSubscribed: yes Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org X-SW-Source: 2012-12/txt/msg00738.txt.bz2 On Thu, 20 Dec 2012 10:13:26 +0100, Metzger, Markus T wrote: > > One can make extension of the syntax to give "record list last 8" > > or even just "record last 8". GDB even provides "alias" command to even > > shorten it for specific user to just "last 8" etc. > > I will think about the "record list" and "record disas" command syntax. > > How do you like temporarily adding debugger variables "$end", "$start", and > "$here" and accepting the same syntax that list and disas accept? I don't > know how difficult that will be to implement, though. I find it overengineered, "record list $end-42" I find already more complicated than a new command "btrace list 42". I do not find great that current record.c numbers history one way and btrace would number history the opposite way. I find the default direction should be the same and it should be easy enough to type each time. > Btw, is anybody actively working on fixing record/replay? Unaware of. Recording of newer features like VEX seems to be missing. > Regarding stepping, reverse-next and reverse-finish will have to operate on > a fake call stack we compute from collecting calls and rets in the branch > trace. I was mentioning only reverse-step. Not reverse-next or reverse-finish, so that one should not need the fake call stack. But as I checked now reverse-step itself already needs a fake call stack for various checks it does. But I find / you are right that implementing even reverse-step is an add-on work, not requiring much to rewrite the existing code. The storage of history information between record.c a btrace.c needs to be completely different anyway. So I agree now the reverse-* compatibility is outside of the scope of the initial commit. > As will next and finish when inside the history. I don't know how > much I will be able to reuse from the record/replay implementation. Probably not at all. Just there should remain the same to_resume/to_wait hooking. > All stepping commands on branch trace will further only affect the current > thread, independent of scheduler-locking. This will be a major difference to > record/replay once that is fixed. OK. > Btw, are you the record/replay maintainer? No, only a user (with IIRC just one fix). Thanks, Jan