Subject: kernel limits (??)
To: None <>
From: Mark Allman <>
List: tech-kern
Date: 10/13/1998 14:00:26

We're having a bit of a problem with a program we have written.  I
think we may be running up against some sort of kernel limit.  And,
I was hoping that maybe a change to a constant might be all that is

Here is the situation...  We have a program that is generating
network traffic.  It splits off into lots of processes, each
handling one TCP flow.  After the connection is terminated the
process goes away.  We can push this until we hit ~230 processes and
then the machine panics in vm_map_entry_create.  We have plenty of
virtual memory on these machines (~1 GB of VM; each process is ~300
KB).  And, looking at the output of "top" right before the crash, it
doesn't look like we're actually pushing against the VM limit at
all.  The last time we ran this test, for instance, the last top
output reported 258 processes and 256 sleeping.  

The "256" stuck out as a sort of magic sounding number.  We bumped
up the number of processes (increased MAXUSERS, which increased
NPROC), so that we have something like a 1000 process limit.  We're
sort of at a loss as to what else we can do.  If anyone has any
ideas about what to do, we would be very interested to hear them.

(Oh, and I am not on this mailing list, so if you reply to the list,
please CC me.  Thanks!).