From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 17094 invoked by alias); 4 Dec 2009 15:35:17 -0000 Received: (qmail 17086 invoked by uid 22791); 4 Dec 2009 15:35:17 -0000 X-SWARE-Spam-Status: No, hits=-1.8 required=5.0 tests=AWL,BAYES_00,SARE_MSGID_LONG40,SPF_PASS X-Spam-Check-By: sourceware.org Received: from mail-ew0-f209.google.com (HELO mail-ew0-f209.google.com) (209.85.219.209) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Fri, 04 Dec 2009 15:35:12 +0000 Received: by ewy1 with SMTP id 1so151295ewy.14 for ; Fri, 04 Dec 2009 07:35:09 -0800 (PST) MIME-Version: 1.0 Received: by 10.213.104.78 with SMTP id n14mr3354999ebo.22.1259940869653; Fri, 04 Dec 2009 07:34:29 -0800 (PST) Date: Fri, 04 Dec 2009 15:35:00 -0000 Message-ID: <5e81cb500912040734u5ce67afdpd6a2d0e63173f908@mail.gmail.com> Subject: UndoDB's performance From: Sean Chen To: 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/msg00027.txt.bz2 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. --=20 Best Regards, Sean Chen