On Tue, May 21, 2002 at 01:14:00PM -0300, Marc G. Fournier wrote:
> Just to confirm, would it be the following that I'm looking at:
...
Nope, further down:
* FreeBSD, threads, and worker MPM. All seems to work fine
if you only have one worker process with many threads. Add
a second worker process and the accept lock seems to be
lost. This might be an APR issue with how it deals with
the child_init hook (i.e. the fcntl lock needs to be resynced).
More examination and analysis is required.
Status: This has also been reported on Cygwin.
Message-ID: <[EMAIL PROTECTED]> (cygnus)
Justin says: So, FreeBSD-CURRENT and Cywin have the same
problem. Yum. If another platform has this
with worker, this becomes a showstopper.
Aaron says: I spent some time disecting this and have come to
the conclusion that it is not a problem in the worker MPM
(or at least, it is not isolated to a problem in worker).
I'll list some of the problems I'm seeing in case someone
else wants to pick up where I've left off:
- Delivery of just about any signal to one of the child
processes will send it into an infinite loop as well.
- Even though the parent is spinning out of control,
at first the child or children will appear to work
properly. At times it is possible to get it into a state,
however, where a request will hang until another concurrent
request "kicks" the first, at which point the second will
hang. My theory is that this has to do with the
pthread_cond_*() implementation in FreeBSD, but it's still
possible that it is in APR.
Justin adds: Oh, FreeBSD threads are implemented entirely with
select()/poll()/longjmp(). Welcome to the nightmare.
So, that means a ktrace output also has the thread
scheduling internals in it (since it is all the same to
the kernel). Which makes it hard to distinguish between
our select() calls and their select() calls.
*bangs head on wall repeatedly* But, some of the libc_r
files have a DBG_MSG #define. This is moderately helpful
when used with -DNO_DETACH. The kernel scheduler isn't
waking up the threads on a select(). Yum. And, I bet
those decrementing select calls have to do with the
scheduler. Time to brush up on our OS fundamentals.
-aaron
