kqueue & pthread
Brian Fundakowski Feldman
green at freebsd.org
Wed Feb 9 07:51:38 PST 2005
On Wed, Feb 09, 2005 at 06:39:52PM +0300, Dmitry Agaphonov wrote:
> On Wed, 9 Feb 2005 09:49:24 -0500
> Brian Fundakowski Feldman <green at freebsd.org> wrote:
>
> BFF> Since you're using user threads, not kernel threads, the kernel can only
> BFF> have one "object" (poll or select list, or kqueue file descriptor) to wait
> BFF> upon at any given time. Since kqueues are pollable, what happens is
> BFF> that the kqueue along with every other fd being polled/selected are all
> BFF> polled by a single poll(2) system call. Yes, your kqueue is being used,
> BFF> but it has an indirection of another poll(2) system call determining
> BFF> when your kevent(2) thread should be woken up.
>
> Brian, thank a lot for your explanation!
>
> So, pthreads since they are user threads do not provide concurrency on
> multiprocessor systems?
Right, the libc_r implementation specifically.
> And by the way, are there another ways to have kernel threads in FreeBSD 4.x
> applications, rather than use LinuxThreads port or implement it via rfork'ed
> processes?
The LinuxThreads library seems to be the best-supported way. I don't think
that there should be legal/licensing issues using it.
--
Brian Fundakowski Feldman \'[ FreeBSD ]''''''''''\
<> green at FreeBSD.org \ The Power to Serve! \
Opinions expressed are my own. \,,,,,,,,,,,,,,,,,,,,,,\
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