Hi,

Miles, you didn't mention which kernel version, I only have sl3x 
machines with 2.4.21x kernels to look at.  Presumably the NUMA stuff is 
different for 2.4 and 2.6 kernels, though I think NUMA exists in 2.4 via 
backporting.  Reviewing kernel startup messages using dmesg will  tell 
you if NUMA is being used:

Scanning NUMA topology in Northbridge 24
Number of nodes: 2 (10010)
Node 0 MemBase 0000000000000000 Limit 000000003fffffff
Node 1 MemBase 0000000040000000 Limit 000000007fff0000
Using node hash shift of 24
Bootmem setup node 0 0000000000000000-000000003fffffff
Bootmem setup node 1 0000000040000000-000000007fff0000

The above is for a 64 bit smp Opteron system booted with kernel options 
numa=on and acpi=off.

As Steven said, the /boot/config* files are helpful.

32 bit athlon smp 2.4.21 kernel:
# CONFIG_X86_NUMA is not set

32 bit intel 2.4.21 smp kernel:
CONFIG_X86_NUMA=y
# CONFIG_X86_NUMAQ is not set

64 bit k8 2.4.21 smp kernel:
CONFIG_K8_NUMA=y
# CONFIG_ACPI_NUMA is not set

Anybody have the Intel 64 bit smp kernel installed?

I think the only Intel NUMA systems are >4 CPU systems, so they are 
pretty rare.

I don't know how much performance difference one is likely to see 
running a dual-Opteron system with and without NUMA.  It would be 
interesting to see some benchmarks.

Cheers,
Tom

Steven J. Yellin wrote:
>     If you installed the kernel in the usual way, in /boot there should be
> a file config<x> with <x> corresponding to whatever rpm was installed.
> For example, /boot/config-2.4.21-37.ELsmp is the file corresponding to the
> kernel-2.4.21-37.ELsmp I installed on my machine. As one might expect from
> the "smp" in the name, it has no line CONFIG_NUMA=y, so NUMA support is
> not enabled.
> 
> Steven Yellin
> 
> On Mon, 7 Nov 2005, Miles O'Neal wrote:
> 
> 
>>Any idea how to tell if an SL3 kernel
>>has NUMA support enabled?
>>
>>Thanks,
>>Miles
>>--
>>Miles O'Neal
>>IT Manager
>>Intrinsity, Inc.
>>[log in to unmask]
>>