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    SubjectRe: SMP performance degradation with sysbench
    J.A. Magallón wrote:
    > On Mon, 26 Feb 2007 23:31:29 -0500, Rik van Riel <riel@redhat.com> wrote:
    >
    >> Hiro Yoshioka wrote:

    >>> Another question. When the number of threads exceeds the number of
    >>> CPU cores, we may get a lot of idle time. Then a workaround of
    >>> MySQL is that do not creat threads which exceeds the number
    >>> of CPU cores. Is it right?
    >> Not really, that would make it impossible for MySQL to
    >> handle more simultaneous database queries than the system
    >> has CPUs.
    >>
    >
    > I don't know myqsl internals, but you assume one thread per query.
    > If its more like Apache, one long living thread for several connections ?

    Yes, they are longer lived client connections. One thread
    per connection, just like Apache.

    > Its the same to answer 4+4 queries than 8 at half the speed, isn't it ?

    That still doesn't fix the potential Linux problem that this
    benchmark identified.

    To clarify: I don't care as much about MySQL performance as
    I care about identifying and fixing this potential bug in
    Linux.

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