Date: Fri, 29 Jul 2005 08:38:44 -0400 From: Martin Cracauer <cracauer@cons.org> To: ray@redshift.com Cc: Martin Cracauer <cracauer@cons.org>, freebsd-amd64@freebsd.org Subject: Re: Benchmarks: AMD64 vs i386 on Dual 246 Opteron Message-ID: <20050729083844.A78480@cons.org> In-Reply-To: <3.0.1.32.20050729023234.00a8afb8@pop.redshift.com>; from ray@redshift.com on Fri, Jul 29, 2005 at 02:32:34AM -0700 References: <3.0.1.32.20050729023234.00a8afb8@pop.redshift.com>
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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 -- %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Martin Cracauer <cracauer@cons.org> http://www.cons.org/cracauer/ No warranty. This email is probably produced by one of my cats stepping on the keys. No, I don't have an infinite number of cats.home | help
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