Configuring workloads for SilkPerformer

This topic describes how to configure a SilkPerformer workload.

Executing transactions

Transactions are a set of actions performed by a script. As shown in Recording-and-replaying-a-basic-SilkPerformer-script, a script's transactions are defined in its dcluser section:

The dcluser section specifies the following:

• Order in which transactions are executed (from top to bottom)
• How frequently transactions are executed

The keywords begin and end can be used in only one transaction per script, and that transaction is executed only once during the simulation. For all transactions that do not contain these keywords, you must specify the execution frequency. For example, in the following code snippet, virtual users execute Transaction1 3 times before moving to the next transaction, Transaction2:

Most situations require each transaction to be executed only once because the workload simulation time regulates the repetition of transactions. The next section, "Setting up workloads," explains how to set up workload simulation time, which determines how long a simulation runs. During the simulation, SilkPerformer runs a script according to the dcluser specification. SilkPerformer repeats the script again and again until the workload simulation time ends. 

Running workloads

When everything is set up, execute your simulation as follows:

1. Choose Run > Run Test.
2. In the Workload Configuration dialog box, click Run.
   A Monitor tab appears to track the progress of the performance test.

You can use the SilkPerformer Automatic Start Monitoring feature to gather statistics for the web server, AR System server, and database systems. This tool works best for Windows operating systems. Alternatively, use each system's Performance Monitor tool to gather statistics.

Setting up workloads

In the Workload Configuration dialog box, you can specify the following:

• Number of users per script
• Simulation time
• Ramp-up time
• Measurement time
• Type of workload to run

To open this dialog box, right-click Workload in the left navigation bar, and choose Edit active workload in the pop-up menu.

SilkPerformer Workload Configuration dialog box

Increasing workload is used most of the time. It enables you to ramp up users successively. For more information about workload types, search for "workload models" in the SilkPerformer Help.

In the above figure, 200 virtual users are divided among seven scripts. A user ramps up every 5 seconds. The simulation runs about 49 minutes, and measurements are taken after all users have logged in at least once.

A queuing workload is used when you know the specific amount of work that needs to be done in a particular time period.  For example, you know that every hour approximately 20 new Incidents are created.  You would specify 20 as the script transaction frequency.

For more information about these settings, search for "workload definition" in the SilkPerformer Help.

You can create as many workloads as necessary, but only one can be active. When you create a workload, make sure you use the correct profile. The active profile should be shown in bold in the left navigation pane of SilkPerformer.

Configuring agents for heavy workloads

Depending on how heavy your workload is, you might need additional SilkPerformer agents to offload the workload so that your SilkPerformer systems do not block your performance testing. To determine whether you need agents, look at CPU and memory use on your current SilkPerformer system. If CPU use is constantly above 70%, you should use agents. The SilkPerformer main driver system (called a controller) collects statistics from the agents and could also generate load. The agents only generate load.

Only SilkPerformer Agent, not the full SilkPerformer application, needs to be installed on agent computers. However, if they already have the full application installed, that can still work as an agent. For agents to recognize each other, they need the same version of SilkPerformer.

For more information, search for "agent" in the SilkPerformer Help.