From owner-freebsd-performance@FreeBSD.ORG Sun Oct 15 06:10:53 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 7017016A403 for ; Sun, 15 Oct 2006 06:10:53 +0000 (UTC) (envelope-from drbrain@segment7.net) Received: from toxic.magnesium.net (toxic.magnesium.net [207.154.84.15]) by mx1.FreeBSD.org (Postfix) with ESMTP id 2CE4E43D58 for ; Sun, 15 Oct 2006 06:10:53 +0000 (GMT) (envelope-from drbrain@segment7.net) Received: from [10.101.28.67] (ziz.jijo.segment7.net [216.254.21.90]) by toxic.magnesium.net (Postfix) with ESMTP id 6963DDA8B7; Sat, 14 Oct 2006 23:10:52 -0700 (PDT) In-Reply-To: <20061013201321.GA774@xor.obsecurity.org> 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> Mime-Version: 1.0 (Apple Message framework v752.2) Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed Message-Id: <39EF1C01-351F-4952-9E9E-0D6A2DBE69C3@segment7.net> Content-Transfer-Encoding: 7bit From: Eric Hodel Date: Sat, 14 Oct 2006 23:10:48 -0700 To: Kris Kennaway X-Mailer: Apple Mail (2.752.2) Cc: freebsd-performance@FreeBSD.ORG 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: Sun, 15 Oct 2006 06:10:53 -0000 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