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    SubjectRe: pipe performance regression on ia64
    >>>>> On Wed, 19 Jan 2005 23:43:45 +1100, Nick Piggin <> said:

    Nick> Oh that's quite true. A bad score on SMP on the pipe benchmark
    Nick> does not mean anything is broken.

    Nick> And IMO, probably many (most?) lmbench tests should be run
    Nick> with all processes bound to the same CPU on SMP systems to get
    Nick> the best repeatability and an indication of the basic serial
    Nick> speed of the operation (which AFAIK is what they aim to
    Nick> measure).

    We need to keep an eye on both the intra- and the inter-cpu
    pipe-bandwidth and should measure them explicitly. The problem is
    that at the moment, we get one, the other, or a mixture of the two,
    subject to the vagaries of the scheduler. If we could reliably
    measure both intra and inter-cpu cases, we may well find new
    optimization opportunities (I'm almost certain that's the case for the
    cross-cpu case; which is probably the more important case, actually).

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