Date: Thu, 6 Aug 1998 09:02:19 +1000 (EST) From: John Birrell <jb@cimlogic.com.au> To: shmit@kublai.com Cc: current@FreeBSD.ORG Subject: Re: Pthreads woes Message-ID: <199808052302.JAA28909@cimlogic.com.au> In-Reply-To: <19980805180913.10635@kublai.com> from Brian Cully at "Aug 5, 98 06:09:13 pm"
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Brian Cully wrote:
> I'm working on a program that spawns a bunch of threads in a pool, each
> of which sits on a condition variable. The main thread waits for
> a RADIUS request on a socket, it signals the condition variable on one
> of the threads in the pool.
>
> The sequence of events is:
>
> main
> ----------------------
> spawn threads
> loop {
> lock thread mutex
> wait for packet
> unlock mutex
You keep the mutex locked while you wait?
> send signal to thread
Signal a condition or a kill() signal?
> }
>
> threads
> ----------------------
> loop {
> wait for signal
> do RADIUS crap
> }
>
> The mutex in question is the same one as used by pthread_cond_wait.
>
> The problem is that I have to wake up the same thread /twice/ before
> it answers a request (IOW, pthread_cond_signal is called twice before
> the thread wakes up and `does RADIUS crap').
>
> I haven't been able to reproduce this in something that isn't so
> complicated (but I can give the full source to anyone who's interested),
> but I was hoping someone might be able to tell me off-the-bat if it's
> a known problem in some instances (or that it's a problem at all).
I do this all the time. In fact I stopped working on such an application
to answer your message.
>
> If not, I'll see what I can do to make the test simpler.
Does the code build cleanly (gcc -Wall) on -current, without using a GNU
configure script, and is it C code (not C++)? If yes, yes and yes, I'll
look at it.
--
John Birrell - jb@cimlogic.com.au; jb@freebsd.org http://www.cimlogic.com.au/
CIMlogic Pty Ltd, GPO Box 117A, Melbourne Vic 3001, Australia +61 418 353 137
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