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From: zink@hare.cdc.com (Ken Zink)
Newsgroups: comp.benchmarks
Subject: Re: How do maxed out users compare to users with think times
Summary: There's no one set of userr characteristics
Message-ID: <34041@shamash.cdc.com>
Date: 11 Jun 91 22:49:16 GMT
Article-I.D.: shamash.34041
References: <676640053.AA19240@flaccid>
Sender: usenet@shamash.cdc.com
Reply-To: zink@udev.cdc.COM (Ken Zink)
Followup-To: comp.benchmarks
Organization: Control Data Corp.
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In article <676640053.AA19240@flaccid> tonys@pyra.co.uk (Tony Shaughnessy) writes:
>
>I am running a benchmark that has been supplied by a customer. The benchmark
>simulates n users (up to 100) entering transactions into the application
> ... without any think times or any simulated typing rate. 
>
>How do I calculate how many real life users these 100 maxed out users simulate?
>
> [ ]
>
>If I try and say that in real life, I will do n TPS, ...
>

I think this is on the right track - represent your system as being capable of
performing n TPS (with the probably silent caveat that there is only about
10 users contending for resources at any one time).  There is no single type
of user!  If the "interators" with your system are themselves intelligent
systems (e.g., programmed PCs), the benchmak may be a correct representation
of the workload.  If the users are clerk/typist performing very repetitive
work, they may achieve a 50 to 60 wpm typing rate (Translate that into
transactions/minute appropriate to whatever they're doing.) with a short
(one or two second) think time.  On the other hand, if the users are
executives, plan on a 2 to 3 wpm typing rate and 20 to 2000 think times.

Again, if the interface is graphic instead of character, the net TPS
is usually higher.

The customer will have to tell you something about the characteristics
of the expected users.  If they can't, I'd suggest presenting your performance
in the form of a set of curves with input rate and think times as the dependent
variables.

Ken