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    SubjectRe: NUMA or not on dual Opteron
    "Justin M. Forbes" <> writes:

    > This is somewhat true. There are 2 types of dual opteron boards. Those in
    > the $200 US range only have one memory bank, which is attached to CPU0.
    > They operate as a single node, and may perform better with numa turned off.
    > Those in the $400+ range tend to have one bank per CPU and will certainly
    > perform better with numa on. They do usually have a bios option to
    > interleave the nodes which would show up as a single node, and probably
    > perform better with numa turned off, but a better solution is to turn off
    > the node interleave in bios and run the kernel with numa support.
    > Basically if you have 2 CPUs and only one memory bank, maybe turning numa
    > off will give better performance, but if you have one memory bank per CPU
    > numa should be on.

    [agreed, except:]

    There is no significant performance difference between NUMA on and off
    on the crippled boards. So best is to always enable CONFIG_NUMA on x86-64.
    The distribution kernels for x86-64 should ship in this configuration

    I would recommend to always disable node interleaved on the non crippled
    board with multiple memory banks. Most boards ship with this disabled by
    default, only a few enable it.

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