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    SubjectRe: Inconsistent timing results of multithreaded program on an SMP machine.
    Date
    On Sun, 20 Nov 2005 21:35, Muli Ben-Yehuda wrote:
    > On Sun, Nov 20, 2005 at 09:28:13PM +1100, Con Kolivas wrote:
    > > Ok I've had a look at the actual program now ;) Are you timing the time
    > > it takes to completion of everything?
    > >
    > > This part of your program:
    > > for (i= 0; i<8; i++)
    > > pthread_join(tid[i], NULL);
    > >
    > > Cares about the order the threads finish. Do you think this might be
    > > affecting your results?
    >
    > I don't see why it should matter. Depending on the order the threads
    > finish, we will always wait in pthread_join until the last one
    > finishes, and then do between 0 and 7 more pthread_joins that should
    > return immediately (since the last one has already finished).

    If it was instant it shouldn't matter. I'm aware of that in theory, but there
    have certainly been reports of pthread_join taking quite a while happening in
    a sort of lazy/sloppy way. I don't know why this is the case but I wondered
    if it was showing up here.

    Cheers,
    Con
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