Date: Fri, 29 Jul 2005 02:32:34 -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: <3.0.1.32.20050729023234.00a8afb8@pop.redshift.com>
next in thread | raw e-mail | index | archive | help
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 seem to remember on one of the first AMD64 installs I did, the apic line produced some sort of compiler error. However, in looking over the AMD64 branch on another machine (with 5.3 on it), I do see there is a SMP config file that includes the GENERIC conf file and then tags on options SMP. So this may be a problem in my benchmarks and I will have to repeat the tests when I have another Dual Opteron server down here. For whatever reason, I was under the impression the AMD64 kernel config file supported SMP by default, but now I'm wondering. Ray
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?3.0.1.32.20050729023234.00a8afb8>