Date: Tue, 02 Aug 2005 09:44:49 +1000 From: Matthew Sullivan <Matthew.Sullivan@canberra.edu.au> To: uidzero <uidzero@bsdhacker.org> Cc: freebsd-amd64@freebsd.org Subject: Re: Benchmarks: AMD64 vs i386 on Dual 246 Opteron Message-ID: <42EEB3F1.9050005@canberra.edu.au> In-Reply-To: <42EA0CA7.8080605@bsdhacker.org> References: <3.0.1.32.20050728013152.00a4d188@pop.redshift.com> <42EA0CA7.8080605@bsdhacker.org>
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uidzero wrote: > ray@redshift.com wrote: > >> Freebsd-AMD64 list: >> >> I recently completed benchmarking an evaluation server provided to us >> by our >> hardware vendor in order to see if switching our cluster from Xeon based >> machines to AMD based machines was worth while/cost effective >> >> The machine provided was a Dual Opteron 246 using the Tyan S2881 >> motherboard. >> It had 4GB or ram and included a single SATA hard drive. >> >> I initially loaded FreeBSD 5.4 AMD64 on the machine, recompiled the >> kernel, etc. >> and applied all the normal tweaks to apache, PHP, etc. The machine, >> while >> faster than our single 2.4 Ghz Xeon's, wasn't all that much faster >> (maybe only >> 10 to 15 percent). >> After speaking with AMD and doing further benchmarks, I was about to >> give up on >> AMD and return the machine. However, at the last minute, an engineer >> from AMD >> suggested that perhaps loading the 32 bit version of FreeBSD (aka >> i386) might >> improve performance, since it was possible that the overhead from 64 bit >> pointers was causing the machine to run slower than expected. He also >> explained >> that the AMD should be running about 3 to 4 times faster than the >> single Xeon. >> >> While this sounded like a long shot, I loaded FreeBSD 5.4 i386 on the >> machine >> and after applying the exact same configuration to the OS, Apache, PHP >> and >> MySQL, re-ran the benchmarks. Much to my surprise, just changing the >> OS from 64 >> bit to 32 bit caused the machine to double in speed. The results are >> attached >> in an Excel spreadsheet. So the exact same machine, running the >> identical >> configuration, performed roughly twice as fast when running FreeBSD >> 5.4 i386 vs >> FreeBSD 5.4 AMD64. Something about this seems so wrong to me :-) >> >> In speaking with one person off the list here, I was told that the >> FreeBSD AMD64 >> branch has actually been cleaned up substantially over the i386 code. So >> naturally I was expecting much better performance from a 64 bit >> machine running >> the AMD64 code than the "older" i386 code. I had also originally >> expected that >> since this branch [the AMD64 branch] was specifically built around the >> AMD >> CPU's, that it should run the best (and thus the fastest) on the AMD >> opteron >> CPU's. However, just the contrary turned out to be the case in >> benchmarking. >> >> I'm wondering if anyone has any comments or thoughts on this? The >> attached >> benchmarks show transactions per second across localhost using Apache >> AB on the >> same machine. The first tests are with plain text files from 64 bytes >> to 50K in >> size. The next group is using a small and medium size PHP program. >> The final >> set relate to MySQL inserts, selects and updates. As you can see from >> the data, >> the exact same machine runs about twice as fast just by switching the >> OS from >> AMD64 to i386. But why? >> >> The only answer I have so far as to why this may be the case is that >> perhaps >> i386 uses 32 bit pointers which the CPU(s) can handle faster (thus >> less overhead >> for the CPU). But it still seems odd to me that if FreeBSD AMD64 is >> written >> specifically for the 64 bit CPU, why doesn't the machine perform >> better when >> running it? >> >> I'm also wondering if there is a compiler switch on AMD64 that could >> be used >> (perhaps in /etc/make.conf or something) that would force the AMD64 >> version to >> run in 32 bit mode only - since that would be an interesting >> comparison as well. >> >> I welcome any/all comments, suggestions, insight. >> Thanks. >> >> Ray >> >> > > Good morning. I'm very NEW to the list and NEW to 64bit systems. I > installed 5.4-R (i386) on my dual AMD64 Opteron 2.0g (1mb cache) with 1g > ram and 4 X 160 (raid10) sata drives server. I was blazing fast, I think > the first kernel recompile was 10 minutes or so "time make buildkernel > KERNCONF=KERNEL" I was shocked to see how fast it was. (I know you > tested with php/etc...) Well, like an idiot, I was thinking I could use > the i386 install disc to get the 64bit. Eh.. no go. I then grabbed the > boot only 64bit from FreeBSD's ftp site and loaded it. Base install of > course. When I did the "first compile" I yet again. was surprised. > 6:29:xx!!! Fastest I've ever seen a kernel compile and that was with ONE > cpu. (Had to compile in SMP.) Man, never had a system that was this fast. > > Needless to say, I think the 64bit out performs the 32bit OSes. Then > again, I'm not as technical as most of you all are, I'm just chimming in > from a "different" side. > > Please, put me in my place if need be. :) This echos my experiences... Further to that I have seen some amazing feats of sheer processing power - processing out Postfix queues of >5k messages (with inline virus checking) on a single AMD64 processor in under 5 minutes (most messages being delivered through a perl script). Mailing lists of 500+ people getting getting processed _and_ delivered in under 20 seconds from first accept to last delivery (450+ users on the list were remote Internet users). As a mail server with inline virus scanning I have no qualms with it receiving 50 messages per second - infact there is a 22M Uplink to the net, so far it has kept up with everything to the point of the 22M being full. Hardware: AMD64 2.0GHz Asus K8S M/B 1G Ram Dual 160G SATA (RAID1 config). Regards, -- Matthew Sullivan IT Security Manager The University of Canberra A member of the Australian Association for the Abolition of Acronym Abuse, Regional Group Headquarters, Strategic and Tactical Operations Planning (AAAAARGHSTOP).
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