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    SubjectRe: lmbench results for 2.4 and 2.5
    > My previous testing with unix sockets prompted me to do a few lmbench 
    > runs with 2.4.19 and 2.5.65. The results have me a bit concerned, as
    > there is no area where 2.5 is faster and several where it is
    > significantly slower.
    >
    > In particular:
    >
    > stat is 8 times worse
    > open/close are 7 times worse
    > fork is twice as expensive
    > tcp latency is 5 times worse
    > file deletion and mmap are both twice as expensive
    > tcp bandwidth is 5 times worse
    >
    > Optimizing for muliple processors and heavy loads is nice, but this
    > looks like its happening at the cost of basic performance. Is this
    > really the route we should be taking?

    I think you're jumping to conclusions about what causes this - let's
    actually try to find the real root cause. These things have many different
    causes ... for instance, rmap has been found to be a problem in some
    workloads (especially things like the fork stuff). If you want to
    try 65-mjb1 with and without the the shared pagetable stuff, you
    may get some different results. (if you have stability problems, try
    doing a patch -p1 -R of 400-shpte, it seems a little fragile right now).

    http://www.kernel.org/pub/linux/kernel/people/mbligh/2.5.65/

    Also, if you can get kernel profiles for each test, that'd help to work
    out the root cause.

    M.

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