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    SubjectRe: [PATCH 1/5] cpuset memory spread basic implementation
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    On Monday 06 February 2006 17:48, Christoph Lameter wrote:

    > This is very different from the typical case of a single threaded process
    > roaming across some data and then terminating. In that case we always want
    > placement of memory as near to the process as possible. In cases were we
    > are not sure about future application behavior it is best to assume that
    > node local is best. Spreading memory allocations for storage that is only
    > accessed from one processor will reduce the performance of an application.
    >
    > So the default operating mode needs to be node local.

    I still don't quite agree. As long as the latency penalty of going
    off node is not too bad (let's say < factor 2) i think it's better
    to spread out the caches than to always locate them locally.
    That is because kernel object/data cache accesses are far less frequent
    than user mapped memory accesses. And it's a good idea to give
    the later memory some headstart for local memory.

    If you have a much worse worst case NUMA factor it might be different,
    but even there it would be a good idea to at least spread it out
    to nearby nodes.

    -Andi

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