Enterprise Library Test Guide - Willy .Net

Testing for Performance and Scalability 171
The following is an example that uses the data in Table 1:
Transactions Per second for ASP.NET = 1844.21
Transactions Per Second for Enterprise Library – January 2006(
instrumentation on) = 1611.7
Overhead = ((1844.21-1611.70)/1844.21)*100) = 12.60%
Initialization Cost
The initialization cost is the cost of preparing an application block so that it can begin
to execute requests. This measurement is not relevant for Web applications because
the first hit (this is the initialization cost) is not considered an important factor in
terms of performance. However, the measurement does matter for smart client applications
because users frequently stop and restart the application.
Consistency
The measurements for response times and use of system resources should be stable
and consistent during performance tests and stress tests. This means that transactions
should always return the expected results and there should be no interruptions of
service. In addition, there should be no spikes in the use of system resources, such as
memory or processors. Transactions that return data should show repeatable results.
Availability
The application block and the computer it runs on should be available. This means
that if there are failures while the application block is running, they should be resolved
before there are problems, such as service errors or corrupted data. For example,
there should be no interruptions of service during the stress tests.
Setting Up the Test Environment
The test environment setup for Enterprise Library requires:
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A host engine for the application blocks.
A network of computers to act as load agents.
Choosing the Host Engine
ASP.NET hosts the application blocks for the Enterprise Library tests. It has the
following advantages:
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ASP.NET is well-documented and has readily available tools to measure
performance and scalability.
ASP.NET allows you to place the client and the server on separate computers.