Information Technology Reference
In-Depth Information
The performance touchpoint paradigm is implemented by tool software
that runs on a different computer than the one used to run the AUT. This
makes the tool computer independent of the number of network-connected
computers running the AUT. In this case, the tool software “observes”
the interactions among the application computers by watching the network
traffic. Theoretically, one performance tool computer could record and
play back an infinite number of client computer sessions to a very large
number of servers. In reality, each client computer playback tool session re-
quires a small but measurable amount of tool computer memory. So the
practical upper limit of the number of client computer sessions that one
performance tool computer can support is in the range of 500 to a few thou-
sand, depending on the tool vendor's design and available tool server memory.
This paradigm becomes even more attractive when you realize that once the
recording session has been completed, zero client computers are required for
the performance tool to play back the script and measure the workload on
the server(s). There are definitely testing resource economies of scale here.
F i g u r e 11. 5 i l l u s t r a t e s t h i s AU T- t e s t t o o l c o m p u t e r r e l a t i o n s h i p fo r p e r fo r m a n c e
testing.
Performance test tool
touchpoint
Intended
end-users
of the
AUT
Could be
100s
Could be
1,000s
...
Server(s) running
the AUT
Performance test tool
executes here
Computers required for
performance test playback
Computers
not
required for
performance test playback
Figure 11.5
Computer(s) necessary to execute performance tests
The really good news for testers is that the two touchpoint paradigms do not
confl ict. Both touchpoint paradigms can be invoked by using functional test tools
and performance test tools at the same testing time in the same testing environment.
Figure 11.6 illustrates how this dual paradigm can work.
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