vmunix on a diet

[Richard Siggs]

In article <7053 at brazos.Rice.edu>, talarian!scott at uunet.uu.net (Scott
Weitzenkamp) writes:
|>After having a SPARCstation 1 (SunOS 4.0.3c) for a couple of months, I
|>finally got around to replacing the GENERIC kernel with a slimmer vmunix.
|>I commented out lots of unnecessary things like quotas, accounting, a
|>second tape drive, etc.  The new kernel file /vmunix is not much smaller
|>(997K vs. 1027K), but it does SEEM to use less memory.  Can anyone out
|>there tell me what utilities are available to get some concrete proof that
|>my new kernel is leaner and meaner?  Thanks...

A relatively simple way that I've used when checking the difference
between the GENERIC & a trimmed down GENERIC (I've done the same thing as
you Scott) is just looking at the figures given out by the 'vmstat'
command. Some of the figures given in fields such as memory free, avm and
the paging & finally the CPU usage fields can tell you a bit of what your
system & kernel is doing.  The 'fre' size from vmstat can give you the
free list, which should be smaller if your kernel uses less memory (all
things being constant).  However, we've noticed (here at the Uni's CS
dept), some 'oddities' with the way that any 'configured' kernel (ie: a
kernel built using the standard linked object files) uses extra physical
RAM for the free-list ONLY, but this shouldn't effect your use of the
'fre' field. I won't elaborate on the free-list vs. RAM usage as I may be
stealing some thunder from the guys here working on the problem, I'm sure
they'll post something once they've sorted it out!