Opteron 4+0 or 4+2 dimm issue

Nakata Maho chat95 at mbox.kyoto-inet.or.jp
Sat Jan 10 07:37:33 PST 2004


Hi, David

> I personally don't like any 4+0 DIMM configuration motherboard -- unless
> it is treated as a 1P Opteron 1xy AGP workstation.  I.E. the K8T
> Master-FAR.  4+0 SMP configuration has NUMA performance issues that can't
> be worked around.  Well, the board still has some merit when used as an
> SMP -- the memory latency across 1-hop is still better than today's
> Pentium-4 SMP systems.

I heard that HyperTransport (6.4G/sec?)
is fast enough so that NUMA is not necessary to implement.

can I ask some question?
in FreeBSD/amd64 with SMP, is it always true that for a process
runs at processor #1 allocates physical memory belongs also to
processor #1?

   process A  -------------------------> accesses DIMM#2
 accesses DIMM#1  <--------------------------   process B
  processor #1 --HyperTransport-- processor #2
     |                                 |
    DIMM    #1                       DIMM #2

if total memory is 2G attached symmetrically, and if
a process allocates near 2G bytes, how physical memory is
allocated?

Regards,
  maho





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