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    SubjectRe: [PATCH] x86: eliminate redundant/contradicting cache line size config options
    On Thu, 19 Nov 2009 04:56:40 +0100
    Ingo Molnar <mingo@elte.hu> wrote:

    >
    > * Nick Piggin <npiggin@suse.de> wrote:
    >
    > > The only other use for L1 cache size macro is to pack objects to
    > > cachelines better (so they always use the fewest number of lines).
    > > But this case is more rare nowadays people don't really count
    > > cachelines anymore, but I think even then it makes sense for it to
    > > be the largest line size in the system because we don't know how
    > > big L1s are, and if you want opimal L1 packing, you likely also
    > > want optimal Ln packing.
    >
    > We could do that - but then this default of X86_INTERNODE_CACHE_SHIFT:
    >
    > + default "7" if NUMA
    >
    > will bite us and turns the 64 bytes L1_CACHE_BYTES into an effective
    > 128 bytes value.
    >
    > So ... are you arguing for an increase of the default x86 linesize to
    > 128 bytes?

    128 is basically always wrong.
    (unless you have a P4... but for default really we should not care
    about those anymore)


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    Arjan van de Ven Intel Open Source Technology Centre
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