Benchmarks: AMD64 vs i386 on Dual 246 Opteron

ray at ray at
Tue Aug 2 17:59:39 GMT 2005

At 10:49 AM 8/2/2005 -0700, David O'Brien wrote:
| On Fri, Jul 29, 2005 at 02:06:09AM -0700, ray at wrote:
| > 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?
| Totally false!  A kernel w/o 'options SMP' is a UP kernel and only uses a
| single CPU.  I suspect is what you are mis-remembering is that an AMD64
| SMP kernel will boot and work just fine on a UP AMD64 machine.  (which
| hasn't been the case on i386 in the past)
| -- 
| -- David  (obrien at

Thanks David - needless to say, I'm going to be re-running all my benchmarks :-D

I can't remember if I left out the SMP line on the AMD kernel config or if I was
thinking about the "device apic" line that is not needed.  I was operating on
about 2 hours of sleep and rushing to finish my benchmarks before the evaluation
server had to be picked up by UPS.  

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.


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