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    SubjectRe: Kernel 2.6 SMP very slow with ServerWorks LE Chipset
    Alan wrote:
    >> As a test of raw CPU power I've been decompressing the kernel tree, with
    >> a UP 2.6 kernel this takes about 1m 15s, I don't know if bz2 is
    >> multithreaded but even if it's not I would expect a slight speed increase
    >> but in fact with a SMP 2.6 kernel it take 13 ~ 26m, with a SMP 2.4
    >> kernel it takes 1m 28s and with a 2.4 UP 1m 35s.
    >
    > The 2.4 numbers look correct (slightly slower), the 2.6 numbers do not.
    >
    >
    > Nothing obviously wrong from the traces however. If you pin the bzip to a
    > given processor do you get different results according to which CPU ?
    >
    > (see man taskset for info on the commands)
    >
    > If you get very different times on the two processors that will be very
    > useful information.

    Mmm CPU 0 in 1m 32s, but I was running things like ps and taskset in
    another terminal to verify affinity, CPU 1 still hadn't finished in 40m
    when I killed it. I've downloaded the LFDK mentioned in the other post
    and will post the results when I have them.

    Thanks for replying,

    This is the script I'm using to time decompression
    nas:~# cat ./cputest.sh
    date
    taskset -c 1 nice -n -8 tar -xjf /root/linux-2.6.18.1.tar.bz2
    date
    uname -a
    rm -r /root/linux-2.6.18.1/
    nas:~#

    both the tar and bzip2 processes have their affinity and priority set by
    the above command.
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