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Pool.pm  view on Meta::CPAN

and before the callback is invoked causes undefined behaviour.

=cut

=item $cpus = AnyEvent::Fork::Pool::ncpu [$default_cpus]

=item ($cpus, $eus) = AnyEvent::Fork::Pool::ncpu [$default_cpus]

Tries to detect the number of CPUs (C<$cpus> often called CPU cores
nowadays) and execution units (C<$eus>) which include e.g. extra
hyperthreaded units). When C<$cpus> cannot be determined reliably,
C<$default_cpus> is returned for both values, or C<1> if it is missing.

For normal CPU bound uses, it is wise to have as many worker processes
as CPUs in the system (C<$cpus>), if nothing else uses the CPU. Using
hyperthreading is usually detrimental to performance, but in those rare
cases where that really helps it might be beneficial to use more workers
(C<$eus>).

Currently, F</proc/cpuinfo> is parsed on GNU/Linux systems for both
C<$cpus> and C<$eus>, and on {Free,Net,Open}BSD, F<sysctl -n hw.ncpu> is
used for C<$cpus>.

Example: create a worker pool with as many workers as CPU cores, or C<2>,
if the actual number could not be determined.

README  view on Meta::CPAN

        Note that there can be considerable time between calling this method
        and the call actually being executed. During this time, the
        parameters passed to this function are effectively read-only -
        modifying them after the call and before the callback is invoked
        causes undefined behaviour.

    $cpus = AnyEvent::Fork::Pool::ncpu [$default_cpus]
    ($cpus, $eus) = AnyEvent::Fork::Pool::ncpu [$default_cpus]
        Tries to detect the number of CPUs ($cpus often called CPU cores
        nowadays) and execution units ($eus) which include e.g. extra
        hyperthreaded units). When $cpus cannot be determined reliably,
        $default_cpus is returned for both values, or 1 if it is missing.

        For normal CPU bound uses, it is wise to have as many worker
        processes as CPUs in the system ($cpus), if nothing else uses the
        CPU. Using hyperthreading is usually detrimental to performance, but
        in those rare cases where that really helps it might be beneficial
        to use more workers ($eus).

        Currently, /proc/cpuinfo is parsed on GNU/Linux systems for both
        $cpus and $eus, and on {Free,Net,Open}BSD, sysctl -n hw.ncpu is used
        for $cpus.

        Example: create a worker pool with as many workers as CPU cores, or
        2, if the actual number could not be determined.