Enterprise Library Test Guide - Willy .Net

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Enterprise Library Test Guide
Also, a NIC’s autonegotiation feature may not properly set the duplex value. You
may have to disable the feature and manually set the NIC to full duplex.
Another problem that can increase network traffic is to host multiple Web controls
on the Web test page. Remove some of the controls to decrease the Web page’s use of
network resources.
Monitoring the Load Agents
A common problem during performance tests is that the load agents use all of the
system resources. Typically, the CPU is the problem. This may be because the transaction
response times are very short. Another reason may be that it is expensive to
create the domain objects that the application block uses. To correct this problem,
increase the number of load agents. An agent should use no more than 75 percent to
80 percent of the CPU.
Monitoring for Locking and Contention
Locking and contention in an application are major performance issues because they
affect the application’s scalability. Use a tool. such as the profiler that is in Visual
Studio Team System. to pinpoint problems that are caused by locked data structures.
To identify contention problems, examine the .NET CLR LocksAndThreads\Contention
Rate/sec performance counter. This counter displays the rate at which the
common language runtime (CLR) unsuccessfully attempts to acquire a managed
lock. Sustained higher values may be a cause of concern, particularly if the application
block uses only a small percentage of the CPU.
Measuring Performance
Each Enterprise Library performance test ran for 5 minutes to 7 minutes. There were
no think times. The warm-up times were 30 seconds. (The warm-up time is used in
a test script to ensure that an application reaches a steady state before the test tool
starts to record results.) Results were recorded every 15 seconds.
Each Enterprise Library stress test ran for 12 hours to 72 hours. There were no think
times. The warm-up time was 5 minutes. Results were recorded every 60 seconds.
Usually, 72 hours with no think times is a good simulation of 2 weeks in a production
environment.
Data collection samples should contain a minimum of 120 samples. Adjust the sampling
interval according to the duration of the test. This is true for both performance
and stress tests. Longer tests should have longer intervals between samples to avoid
too many measurements and filling up the media store.