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    SubjectRe: bug in select() (was Re: {sys_,/dev/}epoll waiting timeout)
    Mark Mielke wrote:
    > On Tue, Jan 28, 2003 at 09:45:00AM +0000, Jamie Lokier wrote:
    > > Davide Libenzi wrote:
    > > > ( if Tms > 0 )
    > > Which is unfortunate, because that doesn't allow for a value of Tms ==
    > > 0 which is needed when you want to sleep and wake up on every jiffie
    > > on systems where HZ >= 1000. Tms == 0 is taken already, to mean do
    > > not wait at all.
    >
    > To some degree, isn't this the equivalent of yield()?

    No. If you want a process to wake every HZ tick, do a little work and
    then sleep again, yield() won't do that.

    If HZ >= 1000, you simply can't use Linux poll() to do that; you have
    to use select(). (Or epoll_wait()).

    Even if select() is changed to do double-rounding-up like poll(), it
    will still do this because select() times have microsecond
    granularity.

    -- Jamie

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