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    SubjectRe: Threading...
    Brian McGrew wrote:
    > On 1/19/07 10:55 AM, "Arjan van de Ven" <> wrote:
    >> On Fri, 2007-01-19 at 10:43 -0800, Brian McGrew wrote:
    >>> I have a very interesting question about something that we're seeing
    >>> happening with threading between Fedora Core 3 and Fedora Core 5. Running
    >>> on Dell PowerEdge 1800 Hardware with a Xeon processor with hyper-threading
    >>> turned on. Both systems are using a kernel (MVP al la special).
    >>> We have a multithreaded application that starts two worker threads. On
    >>> Fedora Core 3 both of these we use getpid() to get the PID of the thread and
    >>> then use set_afinity to assign each thread to it's own CPU. Both threads
    >>> run almost symmetrically even on their given CPU watching the system
    >>> monitor.
    >> this is odd; even in FC3 getpid() is supposed to return the process ID
    >> not the thread ID
    >>> What am I missing? What do I need to do in FC5 or the kernel or the
    >>> threading library to get my threads to run in symmetric parallel again???
    >> you should fix the app to use something like pthread_self() instead...
    >> (or the highly unportable gettid() but that would just be horrible)
    > -----
    > And on FC5 I am using pthread_self but my problem isn't simply with
    > pthread_self, it's with the scheduling. On FC3 both threads run
    > simultaneously in almost symmetric parallel. On FC5 one thread don't pick
    > up and start until the previous one is done. On FC3, using getpid for the
    > thread I could use set_afinity to force each thread to its own processor and
    > with FC5 I can't; so I've got one idle processor all the time.
    This sounds so unlikely I hesitate to mention it, but you are not, by
    any chance, running pthreads on one and nptl on the other, are you?

    bill davidsen <>
    CTO TMR Associates, Inc
    Doing interesting things with small computers since 1979
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