On 19/06/17(Mon) 11:15, Hrvoje Popovski wrote:
> On 19.6.2017. 10:25, Martin Pieuchot wrote:
> > On 15/06/17(Thu) 18:43, Hrvoje Popovski wrote:
> >> Hi all,
> >> test box is configured with kern.pool_debug=1 and option MP_LOCKDEBUG.
> >> while sending traffic (9000 byte) over ix interfaces and at the same
> >> time changing mtu on sink interface (ix1) from 9000 to 1500 drops me to
> >> ddb console.
> >> it seems that i can't trigger dropping to ddb console with
> >> kern.pool_debug=0.
> > But the machine do not freeze right?
> > Do you still enter DDB with a bigger value of __mp_lock_spinout?
> Don't know what that means ...
That means that MP_LOCKDEBUG works the following way:
- Each time you spin on the lock without taking it a counter is increased
- If this counter reaches the value of __mp_lock_spinout the machine enter DDB
So if this value is too small you will enter DDB everytime there's
contention. If it's too big you'll have to wait minutes before entering
I just suggested you increase the default value:
RCS file: /cvs/src/sys/kern/kern_lock.c,v
retrieving revision 1.49
diff -u -p -r1.49 kern_lock.c
--- kern/kern_lock.c 20 Apr 2017 15:06:47 -0000 1.49
+++ kern/kern_lock.c 19 Jun 2017 09:22:39 -0000
@@ -43,7 +43,7 @@
/* CPU-dependent timing, this needs to be settable from ddb. */
-int __mp_lock_spinout = 200000000;
+int __mp_lock_spinout = 2000000000;