Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!spool.mu.edu!uwm.edu!linac!att!princeton!njin!uupsi!cai.com!gupta
From: gupta@cai.com
Newsgroups: comp.databases
Subject: Re: Response from DBMS Editor in Chief, Kevin Strehlo
Message-ID: <386.2818948b@cai.com>
Date: 26 Apr 91 20:58:51 GMT
References: <1991Apr24.152833.3214@drd.com>
Distribution: na
Organization: Computer Associates International
Lines: 43

In article <1991Apr24.152833.3214@drd.com>, mark@drd.com (Mark Lawrence) writes:
> --begin included text
> [...]
>
> We don't mind criticism.  We just like it to be accurate.
> 
> Kevin Strehlo
> DBMS Magazine
> --end encluded text
> -- 
> mark@drd.com
> mark@jnoc.go.jp  $B!J%^!<%/!&%i%l%s%9!K(B  Nihil novum sub solem

The usefulness of a benchmark is that it points out a fact that may not
be otherwise obvious.  If we know beforehand that Operating system 1 (SCO
UNIX) provides symmetric multiprocessing while Operating system 2 (OS/2)
requires all database work and substantial OS work to be done by a single
CPU (except for LAN I/O and file system code), and a dual-cpu machine
is used for benchmarking, then the multi-user performance of the machine
running Operating system 1 (UNIX) is likely to be twice as fast as
Operating system 2 (OS/2).  I leave it to the net to decide whether an
elaborate benchmark is needed to prove this.

However, it would be extremely useful to know which operating system is
better on a single-cpu machine with 16MB of memory (if that is the maximum
that OS/2 can support).  This might give us insights into which operating
is actually better.  For example, what is the overhead of context switches?
What is the I/O performance under these operating systems?  What is the
overhead of inter-process communication?  Etc.

Benchmarking is very hard (I know).  It is very important that at its
conclusion one is very clear about what the benchmark has proven.  The
DBMS magazine article confirms that if I had a dual-CPU server I should
use SCO's MPX option for UNIX (an operating system that supports
symmetric multi-processing) as opposed to OS/2.  However, if I have a
single-CPU server, I could not draw the same conclusions.  Can you?

Regards,
Yogesh Gupta

Disclaimer:
   The opinions expressed in this article are mine and do not represent
   the opinions of anyone else.  If you agree with me ...