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    SubjectRe: Kernel Scalability
    On 5/2/07, Daniel J Blueman <> wrote:
    > There are 128-processor IA64 systems which run recent 2.6 kernels out
    > there; the per-processor counters, RCU and page-fault scalability work
    > has been instrumental to the necessary scaling for decent resource
    > usage on these.

    128 cpu is a bit dated ... there are 512 and 1024 cpu systems being
    used in production environments. The highest reported count stands
    at 4096 ... but that was only a prototype system, not a production
    machine ... a small number of patches were needed to boot (e.g.
    with 10 kernel daemons per cpu, a default kernel hits the maximum
    number of process ids limit!).

    The question of how well it scales is very workload dependent. Most
    of those high cpu count systems are running scientific workloads that
    crunch numbers in user mode for 7.5 million years before making a
    single syscall to print that the answer is 42. Obviously scaling of
    such applications is near linear.

    But your original question was about 4-8 cpus with 2.4/2.6 ... you
    will almost certainly be a lot happier with a recent 2.6 kernel. A
    great deal of work has been done to make it scale well. But
    there are still some dark corners that haven't been cleaned up
    so you will have to run your target application and make your
    own measurments on scaling. If you find that it doesn't scale
    well, then we'd like to hear about it here.

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      Last update: 2007-05-02 18:57    [W:0.030 / U:8.872 seconds]
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