[mod.os] Measurement of operating system "Overhead"

darrell@sdcsvax.UUCP (02/14/87)

I'm looking for:

1) definitions of operating system overhead

2) estimations or measurements of overhead for real systems,
   preferablly mainframes or supercomputers

3) arguments for or against using overhead as a way to compare
   operating systems.

Any leads would be appreciated.

Marty

darrell@sdcsvax.UUCP (02/18/87)

Does anyone have any good ideas on how to quantify the
performance of a fileserver?  We have an Ethernet with 40 MG1
workstations using NFS to mount filestores from three servers.
We need a way of measuring the quality of a server's
performance, so that we can make an informed choice of what
hardware to use when upgrading the servers.

The problems appear to be:

1) Relativity

   Server load depends on what the clients ask for, so you need
   to know what all the clients are doing as well.

2) Interference

   We can't dedicate any of our hardware exclusively to fileserving
   so the "background load" needs to be taken into consideration.

3) Uh, What's the Question?

   We don't know what units our answer should be given in -
   (mean time until service) per client?


This is "Benchmarkers Stone" stuff and so I don't expect
complete answers, but does anyone have any suggestions at all?
-- 

William Roberts         ARPA: liam@cs.qmc.ac.uk  (gw: cs.ucl.edu)
Queen Mary College      UUCP: liam@qmc-cs.UUCP
LONDON, UK              Tel:  01-980 4811 ext 3900