Benchmarks: AMD64 vs i386 on Dual 246 Opteron

[David O'Brien]

On Tue, Aug 02, 2005 at 10:59:41AM -0700, ray at redshift.com wrote:
> Thanks David - needless to say, I'm going to be re-running all my benchmarks
...
> I'll post my results when I have another machine in here and re-run the exact
> same benchmarks.  This time I will be certain to confirm the situation on the
> SMP kernel with regard to the AMD64 branch.

You need to be careful about what you are testing.
If you dual-boot 64-bit and 32-bit from the same disk, don't forget one
of them will be on a faster area of the disk.  So you need a 2nd data
disk that is newfs'ed between each run to do your benchmarks on.

At a minium, you should build a set of 32-bit binaries on FreeBSD/i386
with CPUTYPE=k8.  Run benchmarks under the 32-bit OS.
Then run the same benchmarks with the 32-bit binaries on the 64-bit OS.
(ie, you're just changing the kernel).
Then build 64-bit binaries and benchmark them.
You should use RELENG_6, not 5.x to make sure you're getting the best K8
GCC we support along with the optimizations we've added since 5.x was
released.
 
-- 
-- David  (obrien at FreeBSD.org)