From owner-freebsd-performance@FreeBSD.ORG Mon Oct 16 18:16:16 2006 Return-Path: X-Original-To: freebsd-performance@freebsd.org Delivered-To: freebsd-performance@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id A33CC16A494 for ; Mon, 16 Oct 2006 18:16:16 +0000 (UTC) (envelope-from chrcoluk@gmail.com) Received: from py-out-1112.google.com (py-out-1112.google.com [64.233.166.179]) by mx1.FreeBSD.org (Postfix) with ESMTP id 524A143D6D for ; Mon, 16 Oct 2006 18:16:03 +0000 (GMT) (envelope-from chrcoluk@gmail.com) Received: by py-out-1112.google.com with SMTP id o67so2359546pye for ; Mon, 16 Oct 2006 11:15:30 -0700 (PDT) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=M+tM2sBxxw3EauxAZpx1iOHQFtAK1/T/uSckM9tPwZW0l3fdINOOYdHiidZ18JR6bB4lBFBpdhojcQ1Wuqt8vAz0DZ1/5HGxtVmvCdD5GQChJeYFSF2zhFLRlbpeZ/p4xYqXuRPN5/TdqJKLZrNwgfktYnzZVs664nQrdqmRvxk= Received: by 10.35.72.1 with SMTP id z1mr13305808pyk; Mon, 16 Oct 2006 11:05:28 -0700 (PDT) Received: by 10.35.29.20 with HTTP; Mon, 16 Oct 2006 11:05:28 -0700 (PDT) Message-ID: <3aaaa3a0610161105m72d0b5d8y17bd1e1835a4d5d4@mail.gmail.com> Date: Mon, 16 Oct 2006 19:05:28 +0100 From: Chris To: "Eric Hodel" In-Reply-To: <39EF1C01-351F-4952-9E9E-0D6A2DBE69C3@segment7.net> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <3731.71.56.92.181.1160009571.squirrel@www.stelesys.com> <200610120925.k9C9PmUK048690@lurza.secnetix.de> <20061012205342.GA62241@xor.obsecurity.org> <9500A2C9-07EB-4EEA-9477-9E6B4BFEB437@mac.com> <20061013201321.GA774@xor.obsecurity.org> <39EF1C01-351F-4952-9E9E-0D6A2DBE69C3@segment7.net> Cc: freebsd-performance@freebsd.org, Kris Kennaway Subject: Re: Help with improving mysql performance on 6.2PRE X-BeenThere: freebsd-performance@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Performance/tuning List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 16 Oct 2006 18:16:16 -0000 On 15/10/06, Eric Hodel wrote: > On Oct 13, 2006, at 1:13 PM, Kris Kennaway wrote: > > On Fri, Oct 13, 2006 at 11:49:04AM -0700, Chuck Swiger wrote: > >> On Oct 13, 2006, at 11:26 AM, Eric Hodel wrote: > >>>>> Or did that change recently? > >>>> > >>>> It's only on certain systems, apparently. > >>> > >>> Is there a list of systems where it is safe to use the TSC with > >>> SMP? Or some script we can run? > >> > >> The problem of the TSC clocks getting out of sync affects pretty much > >> all AMD X2 dual-core CPUs, as well as the older 32-bit Althon MP > >> CPUs; the Intel Xeon and Core Duo CPUs seem to do a lot better, > >> although older Intel CPUs have also been reported to show problems > >> with the TSC. > > > > Beyond that, just see if it works ;-) > > How "safe" is it to switch timecounters? I don't have a spare > machine to test on... > > From my readings on switching the TSC over the past several months I > think that if it doesn't work I'll see is ntpd adjusting my system > clock more often (or falling out of sync). I don't know if this will > corrupt mysql while its running though (which is my fear). > > FWIW I have a "Dual Core AMD Opteron(tm) Processor 270". > > -- > Eric Hodel - drbrain@segment7.net - http://blog.segment7.net > This implementation is HODEL-HASH-9600 compliant > > http://trackmap.robotcoop.com > > > _______________________________________________ I switched from the default timer to TSC on a dual xeon setup and my loads instantly went up with mysql lagging, so in my case it was much worse. Chris