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    SubjectRe: CPA patchset
    On Fri, 11 Jan 2008, Ingo Molnar wrote:

    > * Andi Kleen <ak@suse.de> wrote:
    >
    > > Cached requires the cache line to be read first before you can write
    > > it.
    >
    > nonsense, and you should know it. It is perfectly possible to construct
    > fully written cachelines, without reading the cacheline first. MOVDQ is
    > SSE1 so on basically in every CPU today - and it is 16 byte aligned and
    > can generate full cacheline writes, _without_ filling in the cacheline
    > first.

    did you mean to write MOVNTPS above?


    > Bulk ops (string ops, etc.) will do full cacheline writes too,
    > without filling in the cacheline.

    on intel with fast strings enabled yes. mind you intel gives hints in
    the documentation these operations don't respect coherence... and i
    asked about this when they posted their memory ordering paper but got no
    response.

    -dean


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