> First, I must say that this all concernes quite current
> CURRENT (Jan 9 or so). I don't know if the same holds for
> older versions.
>
> I'm kind of puzzled.
>
> I've a simple sample program (see at the bottom). It creates 10
> threads with start function start_my_thread(), and then runs the
> same function in main(). So, we have 11 threads doing the same job.
>
> Function start_my_thread() just increments indefinitely counters
> (each thread has its own counter).
>
> Program, when killed with SIGINT, prints all counters and exits.
>
> Now, as I understand, userspace threads in FreeBSD are preemptive.
> So, though my 11 threads are all computational and do not do
> any syscalls, sleeps, sched_yield, whatever -- newertheless,
> the program should not be stuck in one thread. And it seems to
> be sometimes true. But only sometimes!
>
> Depending on the phase of the moon (it seems) sometimes my
> program gives (after ^C):
>
> ^C
> Thread 0x00: 0
> Thread 0x01: 0
> Thread 0x02: 0
> Thread 0x03: 0
> Thread 0x04: 0
> Thread 0x05: 0
> Thread 0x06: 0
> Thread 0x07: 0
> Thread 0x08: 0
> Thread 0x09: 0
> Thread 0x0a: 488133092
OK, with everyones help (well, waiting for the right time of day ;-)), I
was able to reproduce this. The initial threads last active time was
not getting initialized to a sane value, causing negative computations
of the threads timeslice depending on what time of day it was. Funny
thing was that I added this change several times, but each time I somehow
convinced myself that it wasn't needed.
Try this patch - you may have to hand apply it as my sources are not
yet up to date with the last round of changes that Jason made.
Dan Eischen
[EMAIL PROTECTED]
Index: uthread_init.c
===================================================================
RCS file: /opt/b/CVS/src/lib/libc_r/uthread/uthread_init.c,v
retrieving revision 1.21
diff -c -r1.21 uthread_init.c
*** uthread_init.c 1999/12/29 15:44:59 1.21
--- uthread_init.c 2000/01/17 11:47:06
***************
*** 92,97 ****
--- 92,98 ----
int mib[2];
struct clockinfo clockinfo;
struct sigaction act;
+ struct timeval tv;
/* Check if this function has already been called: */
if (_thread_initial)
***************
*** 222,227 ****
--- 223,233 ----
/* Initialize the owned mutex queue and count: */
TAILQ_INIT(&(_thread_initial->mutexq));
_thread_initial->priority_mutex_count = 0;
+
+ /* Initialize last active time to now: */
+ gettimeofday(&tv, NULL);
+ _thread_initial->last_active.tv_sec = tv.tv_sec;
+ _thread_initial->last_active.tv_usec = tv.tv_usec;
/* Initialise the rest of the fields: */
_thread_initial->poll_data.nfds = 0;
