Date: Fri, 12 Mar 2004 15:31:26 -0500 From: Jem Matzan <valour@thejemreport.com> To: freebsd-amd64@freebsd.org Subject: Re: Peer review of AMD64/FreeBSD article Message-ID: <40521E1E.4060502@thejemreport.com> In-Reply-To: <20040312183543.GC60405@curacao.n2it.nl> References: <4051A841.9020205@thejemreport.com> <200403121301.i2CD1oQC076505@lurza.secnetix.de> <20040312183543.GC60405@curacao.n2it.nl>
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Bill Squire wrote: >On Fri, Mar 12, 2004 at 02:01:50PM +0100, Oliver Fromme wrote: > > >>Jem Matzan <valour@thejemreport.com> wrote: >> > I've just finished writing this article comparing performance between an >> > Athlon64 in 32-bit and 64-bit mode using FreeBSD: >> > >> > http://www.thejemreport.com/lab64/amd64vsi386.php >> > >> > (this is a temporary address which will later redirect to the published >> > article) >> > >> > I've checked it over twice for fact accuracy, but I would like other >> > eyes to look at it before it goes to press. I haven't spell-checked it >> > yet, so don't worry about that... I just want to make sure I haven't >> > made any factual errors. >> >>I like the article very much. Well done. I also appre- >>ciate the fact that you refrained from spoiling the compa- >>rison with colorful graphics. :-) >> >>There are just two things which seem a bit unclear to me. >> >>In the very first paragraph it sounds like hyperthreading >>would always be a performance win, but that's not the case. >>I've had applications that ran slightly faster when hyper- >>threading was turned off. If I remember correctly, soft- >>ware that does many concurrent things and I/O benefits most >>from hyperthreading, while pure numbercrunching jobs run >>faster with hyperthreading switched off. (I'm not saying >>that you should repeat all your benchmarks with hyper- >>threading off, mind you. I just think that the remark in >>the first paragraph sounds a little bit misleading. YMMV.) >> >>The second point is that the gcc "benchmark" seems a bit >>unfair for me, because you're really measuring _different_ >>things when compiling something for i386 and for amd64. >>The compiler is producing different code, it has to opti- >>mize differently (particularly because of the different >>register sets of the processors), so you can't really >>compare the results. Also take into account that the amd64 >>code generation engine of gcc is rather new, while the i386 >>code generation is very mature. Apart from that, I would >>rather call this "benchmark" synthetic, because nobody buys >>an Opteron to compile things all day long. Well, except >>for the FreeBSD package building people, maybe. :-) >> >>In relation to that, the oggenc benchmark is certainly much >>more realistic. It would have been nice to have some video >>decoding / encoding benchmarks, too (e.g. mplayer / menco- >>der, transcode, ffmpeg, whatever). >> >>Well, just my 2 cents. :-) >> >>Regards >> Oliver >> >> >> > >Hi Oliver, > >Your name seems familiar to me. Anyways, as far as benchmarks there is >allot of 'snake oil' for salesmen out there. This is the coolest bench >mark for hardware I've ever seen. It is extremely technical and do >understand it or limit your experiment. ><http://www.kurims.kyoto-u.ac.jp/~ooura/fft.html>; > >Good luck, (everyone -- this is fun stuff) > >Bill > >PS: My EUR 0,02 worth (Actually free and ALLOT of time went into getting >this right.) You should be able to get 4M (2^22) digits of pi in about >2:22s with a single amd64 running at 2.22GHz. :) The performance rating >of a well tuned amd64 is over 5600, the beat Intel barely gets 3000 and >uh won't spoil the fun, but "The fastest desktop ever" (as the ads in the >sheepish trash once read.) Will not likely beat the Intel, but I don't >waste my time on closed source. > > > > > > > >_______________________________________________ >freebsd-amd64@freebsd.org mailing list >http://lists.freebsd.org/mailman/listinfo/freebsd-amd64 >To unsubscribe, send any mail to "freebsd-amd64-unsubscribe@freebsd.org" > > > > Alas it's not in ports... I'd rather have a standard version to go from, knowing that the code will work well with FreeBSD 5.2.1-RELEASE. It looks like a good test though; I'm going to try it out anyway for my next round of testing. I'm particularly interested in valid tests that can accurately show performance differences between architectures. -Jem
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