Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!ames!umd5!brl-adm!adm!weiser.pa@xerox.com
From: weiser.pa@xerox.com
Newsgroups: comp.unix.wizards
Subject: Vax 11/780 performance vs Sun 4/280 performance
Message-ID: <14968@brl-adm.ARPA>
Date: 27 May 88 17:08:54 GMT
Sender: news@brl-adm.ARPA
Lines: 13

What your DEC salesperson may have heard, undoubtedly very indirectly, is that
there is a knee in the performance curve of the Sun-4/280 at > 15 processes
ready-to-run.  This has nothing to do with > 15 users: more like a load average
of > 15.  Do your vaxes ever run with a load average of > 15?  If not, ok.  But,
if they EVER hit 16 or 17, watch out on the Sun-4's:  I can trivially get my
Sun-4 completely wedged so I have to reboot with L1-A by just starting 19 little
processes which sleep for 100ms, wake-up and sleep again.  This doesn't even
raise the load average (but amounts to a load average of 19 to the context
switching mechanism, although not to the cpu).

And the Sun-3's are no better: the knee there is >7 processes.

-mark