Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!apple!sun-barr!decwrl!decvax!ima!minya!jc
From: jc@minya.UUCP (John Chambers)
Newsgroups: comp.unix.wizards
Subject: Re: Record High Load Average
Message-ID: <3@minya.UUCP>
Date: 18 May 89 01:14:09 GMT
References: <1704@ucsd.EDU> <273@indri.primate.wisc.edu>
Organization: (none)
Lines: 35

In article <273@indri.primate.wisc.edu>, bin@primate.wisc.edu (Brain in Neutral) writes:
> From article <1704@ucsd.EDU>, by brian@ucsd.EDU (Brian Kantor):
> > 
> > Yesterday we got our network connections unjammed and our mail gateway
> > 'UCSD' set what I think may be the record for a Vax-750: 85.3.  And this
> > is on a machine which has NO users, just sendmails.
> 
> I once got up over 50 for a short while on my VAXstation 2000 under
> similar circumstances.  It made my surface plot of the month's activity
> look a bit strange; large areas of slightly ripply plains surrounding
> the tower of Babylon.
> 
> > Truly a frightful experience.
> 
> That's for sure...

Not necessarily.  A couple of years back, I wrote a little program 
that added N to the load average without affecting performance.  The 
point was to explain to people why the load average was not necessarily 
a good measure of anything.

The program wasn't very tricky.  It just called nice(40), forked off 
N-1 copies, and each went into an infinite loop.  The result was N
cpu-hog processes, all running at the lowest priority, and using close
to 0 memory.  As a normal user, there was a limit of 20 processes,
but on machines where I knew the root password, I could (and did)
demonstrate load averages of 50 or 60 without any detectable impact
on response time for vi or emacs users.  The end-of-month statistics
on those machines drew a bit of attention....

-- 
John Chambers <{adelie,ima,mit-eddie}!minya!{jc,root}> (617/484-6393)

[Any errors in the above are due to failures in the logic of the keyboard,
not in the fingers that did the typing.]