From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 1848 invoked by alias); 14 Dec 2009 11:14:55 -0000 Received: (qmail 1838 invoked by uid 22791); 14 Dec 2009 11:14:54 -0000 X-SWARE-Spam-Status: No, hits=-1.7 required=5.0 tests=AWL,BAYES_00,SARE_MSGID_LONG40,SPF_PASS X-Spam-Check-By: sourceware.org Received: from mail-iw0-f203.google.com (HELO mail-iw0-f203.google.com) (209.85.223.203) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Mon, 14 Dec 2009 11:14:49 +0000 Received: by iwn41 with SMTP id 41so1756879iwn.12 for ; Mon, 14 Dec 2009 03:14:48 -0800 (PST) MIME-Version: 1.0 Received: by 10.231.167.204 with SMTP id r12mr1161463iby.31.1260789288123; Mon, 14 Dec 2009 03:14:48 -0800 (PST) In-Reply-To: <5e81cb500912040734u5ce67afdpd6a2d0e63173f908@mail.gmail.com> References: <5e81cb500912040734u5ce67afdpd6a2d0e63173f908@mail.gmail.com> From: Hui Zhu Date: Mon, 14 Dec 2009 11:14:00 -0000 Message-ID: Subject: Re: UndoDB's performance To: Sean Chen Cc: gdb@sourceware.org Content-Type: text/plain; charset=windows-1252 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/msg00083.txt.bz2 gdb-7 reverse debugging accelerator. Regular gdb-7 reverse runs apps 40,000x slower=09 UndoDB+gdb-7 reverse runs apps 1.7x slower! Are you really do some try? I suggest you do some test on it. :) Thanks, Hui On Fri, Dec 4, 2009 at 23:34, Sean Chen wrote: > On UndoDb=92s website, I saw the following ad. > > Regular gdb-7 reverse runs apps 40,000x slower > UndoDB+gdb-7 reverse runs apps 1.7x slower! > > In my experiment, gdb-7 reverse does run apps more than 20,000x > slower. How does UndoDB improve the performance so much without a > simulator and without record? Below is its self-introduction on the > website. UndoDB's "snapshot-and-replay" technique stores periodic > copy-on-write snapshots of the application and only non-deterministic > inputs (system calls, thread-switches, shared memory reads, etc). > > Are there any obvious disadvantages in UndoDB? I tried to search > UndoDB in the archive of the mailing list, however, little discussion > is found. > > -- > Best Regards, > Sean Chen >