Date: Fri, 29 Jul 2005 05:43:36 -0700 From: ray@redshift.com To: Martin Cracauer <cracauer@cons.org> Cc: Martin Cracauer <cracauer@cons.org>, freebsd-amd64@freebsd.org Subject: Re: Benchmarks: AMD64 vs i386 on Dual 246 Opteron Message-ID: <3.0.1.32.20050729054336.00a67578@pop.redshift.com> In-Reply-To: <20050729083844.A78480@cons.org> References: <3.0.1.32.20050729023234.00a8afb8@pop.redshift.com> <3.0.1.32.20050729023234.00a8afb8@pop.redshift.com>
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At 08:38 AM 7/29/2005 -0400, Martin Cracauer wrote: | ray@redshift.com wrote on Fri, Jul 29, 2005 at 02:32:34AM -0700: | > 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. | > | > On the AMD64, I am pretty sure that I did *not* include the following lines like | > I normally do on the i386: | > | > options SMP # Symmetric MultiProcessor Kernel | > device apic # I/O APIC | | I occurse to me that not using one of the two CPUs might have | something to do with a performance drop of approximately 50% :-) | | Martin :-) Stay tuned for "son of benchmarks" when I get our next Dual Opteron 246 in here! This may be operator, not "opteron" error after all - hehe :) Ray
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