From owner-freebsd-amd64@FreeBSD.ORG Fri Mar 12 11:44:23 2004 Return-Path: Delivered-To: freebsd-amd64@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 29D7F16A4CE for ; Fri, 12 Mar 2004 11:44:23 -0800 (PST) Received: from host142.ipowerweb.com (host142.ipowerweb.com [66.235.193.61]) by mx1.FreeBSD.org (Postfix) with SMTP id EB0A243D2D for ; Fri, 12 Mar 2004 11:44:22 -0800 (PST) (envelope-from valour@thejemreport.com) Received: (qmail 60142 invoked from network); 12 Mar 2004 19:43:42 -0000 Received: from unknown (HELO thejemreport.com) (66.67.130.234) by host142.ipowerweb.com with SMTP; 12 Mar 2004 19:43:42 -0000 Message-ID: <4052130E.9060601@thejemreport.com> Date: Fri, 12 Mar 2004 14:44:14 -0500 From: Jem Matzan User-Agent: Mozilla/5.0 (X11; U; FreeBSD i386; en-US; rv:1.6) Gecko/20040219 X-Accept-Language: en-us, en MIME-Version: 1.0 To: freebsd-amd64@freebsd.org References: <200403121301.i2CD1oQC076505@lurza.secnetix.de> <4051B7D3.8020404@thejemreport.com> <20040312174736.GD7661@Odin.AC.HMC.Edu> In-Reply-To: <20040312174736.GD7661@Odin.AC.HMC.Edu> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: Peer review of AMD64/FreeBSD article X-BeenThere: freebsd-amd64@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Porting FreeBSD to the AMD64 platform List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 12 Mar 2004 19:44:23 -0000 Brooks Davis wrote: >On Fri, Mar 12, 2004 at 08:14:59AM -0500, Jem Matzan wrote: > > >>Hyper-Threading seemed to help with processes that didn't require a >>heavy CPU load. The OpenSSL tests show it being markedly faster in the >>smaller algorithms, but lagging way behind the 64-bit Athlon64 when the >>serious number crunching comes into play. Intel's press kit shows HT >>(and SSE3) giving an advantage when multitasking with four desktop >>programs in Windows XP. It's just too hard to show that reliably though. >>There's a lot of anecdotal evidence to suggest that AMD64 is faster on >>the desktop (in X) in 64-bit mode than the Prescott is in 32-bit, but >>I'm having trouble proving it. >> >> > >I think it would be a mistake to assume the HT is what accounts for >the performance difference. There are so many other architectural >differences it's hard to see how you could isolate the effects of >HT. My suspicition is that better performance on small >algorithms is due to them being more or less memory bound (and thus >similar to the pure synthetic benchmarks). > >-- Brooks > > > By comparing the Pentium4 to the Athlon64 in i386 mode, you can better see the advantage of HT Technology. This is especially evident in the OpenSSL tests. -Jem