Date: Fri, 29 Jul 2005 02:06:09 -0700 From: ray@redshift.com To: Martin Cracauer <cracauer@cons.org> Cc: freebsd-amd64@freebsd.org Subject: Re: Benchmarks: AMD64 vs i386 on Dual 246 Opteron Message-ID: <3.0.1.32.20050729020609.00a6a240@pop.redshift.com> In-Reply-To: <20050728193519.A66123@cons.org> References: <3.0.1.32.20050728013152.00a4d188@pop.redshift.com> <3.0.1.32.20050728013152.00a4d188@pop.redshift.com>
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At 07:35 PM 7/28/2005 -0400, Martin Cracauer wrote: | > 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 :-) | | I'm sorry but I cannot support these findings. I don't have | cut'n'paste numbers handy, but generally 64 bits speed up things quite | a bit for me. I have seen slowdown in 64 bit mode in e.g. bzip2 but | generally there is a speedup. Hi Martin - do you have any data to back up these statements? If so, I'd like to see it. I will have another AMD Dual Opteron in here in a month or so and will do some further benchmarks. In going over my notes, the only thing I can see that might have been a mistake was if I left out 'options SMP' from the AMD64 kernel config file. But I seem to recall you do not have to include that on AMD64 like you do with i386 - can anyone confirm this? I had to return the evaluation server, so I can't test it this second. As far as I call, the CPU's were launching properly under both installations however. When I have our next AMD Dual Opteron machine in here, I will re-run the tests. Ray
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