[geeks] Drool-worthy

[Joshua Boyd]

On Wed, Nov 10, 2004 at 08:38:38PM +0000, Mike Meredith wrote:

> * The AMD Opteron is a NUMA system ? I suppose it might have on chip
>   support for some NUMA architecture, but surely NUMA is more the system
>   than just the CPU ?

I agree that NUMA takes more than one CPU.

My understanding of multi CPU Opteron systems sounds pretty NUMA though.
Each CPU has it's own memory.  The CPUs can also communicate directly
with other CPUs, and when it wants to use memory not attached to itself,
it sends requests to the other CPU.  Also, I believe each CPU has two
such communications channels, so quad CPU machines form a ring for
communications.   So, in short, it seems to me that NUMA support is
built directly into the CPUs.

What's not clear to me is if it is also possible to do regular SMP
instead of NUMA with Opterons.

If you google for NUMA and opteron, you will find a lot of interesting
stuff. 

I think Opterons are fairly cool looking.  I wish someone would build
true legacy free machines around them, and I don't mean the wimpy Intel
Legacy-free standard, but to even do away with the BIOS and to also
start the machine up in 64bit mode rather than requiring the OS to
bootstrap from 16bit up to 64bit.


-- 
Joshua D. Boyd
jdboyd at jdboyd.net
http://www.jdboyd.net/
http://www.joshuaboyd.org/