As part of my ongoing plan to work out why NetBSD/arm32 is locking up
on a variety of installations under medium load, I simulated 40 users
accessing web-based email accessing a localhost IMAP server.

This will start up a whole load of httpd (Apache 1.3.1) processes
talking to a load of copies of a C cgi program which then in turn talk to
a lot of imapd's spawned by inetd.

The machine dies in a variety of interesting ways (never quite the same
twice!)

A couple of times, it carried on working but kept spewing out the word
"issignal"

A couple of times it completely locked.

Once a drop to db> with trace:

_panic
_pmap_enter
_pmap_pinit
_pmap_create
_uvmspace_init
_uvmspace_alloc
_uvmspace_fork
_uvm_fork
_fork1
_sys_fork
_syscall

This machine is an 18MB RiscPC, so it swaps like crazy. Increasing the RAM
to 50MB fixed all the problems which was a pleasant surprise, however the
system shouldn't become so unstable with less RAM, IMHO.

Stephen Borrill