From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 24088 invoked by alias); 11 Dec 2009 13:24:59 -0000 Received: (qmail 24071 invoked by uid 22791); 11 Dec 2009 13:24:55 -0000 X-SWARE-Spam-Status: No, hits=-2.3 required=5.0 tests=AWL,BAYES_00 X-Spam-Check-By: sourceware.org Received: from web112506.mail.gq1.yahoo.com (HELO web112506.mail.gq1.yahoo.com) (98.137.26.142) by sourceware.org (qpsmtpd/0.43rc1) with SMTP; Fri, 11 Dec 2009 13:24:51 +0000 Received: (qmail 16613 invoked by uid 60001); 11 Dec 2009 13:24:50 -0000 Message-ID: <947215.16059.qm@web112506.mail.gq1.yahoo.com> Received: from [123.237.137.157] by web112506.mail.gq1.yahoo.com via HTTP; Fri, 11 Dec 2009 05:24:49 PST References: <816087.35180.qm@web112515.mail.gq1.yahoo.com> <4B218B30.4010501@vmware.com> <119734.20965.qm@web112506.mail.gq1.yahoo.com> <4B21B85F.1030502@vmware.com> <5e81cb500912101948nb8b09e8j7d58f6332ec62a38@mail.gmail.com> <008401ca7a3a$272f65f0$758e31d0$@com> Date: Fri, 11 Dec 2009 13:24:00 -0000 From: paawan oza Subject: Re: porting reversible on arm/mips To: Jakob Engblom , Sean Chen , Michael Snyder Cc: Hui Zhu , gdb@sourceware.org In-Reply-To: <008401ca7a3a$272f65f0$758e31d0$@com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable 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: 2009-12/txt/msg00072.txt.bz2 I am not sure how arm can be drastically slower than x86 ! considering arm = 32 bit. but at the first point, if in some way if prec arch level stuff and abis re= lated framework are in place, then optimization on the same may lead us to get faster recording like cach= e implementation and so on. But I am not sure of any specific reason why on arm it could be very slower= , having the same conf as x86.=20 Regards, Oza. ----- Original Message ---- From: Jakob Engblom To: Sean Chen ; Michael Snyder Cc: paawan oza ; Hui Zhu ; gdb@so= urceware.org Sent: Fri, December 11, 2009 1:45:48 PM Subject: RE: porting reversible on arm/mips > I was interested in the porting on ARM. But later I found that the > performance impact on ARM might damage the usage of process record. In > my experiment, reversible debugging is about 20000x slower, which > might be endurable on the modern computer. However, ARM target is tens > of times (or even more if we consider the memory) slower than PC. So > recording instructions will be very slow, about thousands of > instructions per second. I just must pitch in and say that it depends on the simulator. An advantage to using a full simulator is that you simplify the system and = no longer have to care about OS calls: the OS is just part of the context you = save and reverse. So the overhead actually goes down compared to native prec. I think a reversible ARM simulator can be made to run within a factor of ten = of native speed, easily.=20 Best regards, /jakob _______________________________________________________ Jakob Engblom, PhD, Technical Marketing Manager Virtutech Direct: +46 8 690 07 47=20=20=20 Drottningholmsv=E4gen 22 Mobile: +46 709 242 646=20=20 11243 Stockholm Web: www.virtutech.com=20 Sweden ________________________________________________________