Configuring the agent's data channel

In some scenarios, it may be necessary to provide some buffering between the agent and the Agent Controller. Buffering is done by using a data channel between the agent and the Agent Controller. Data channels are desirable in situations where agent performance is highly important. Without a buffer, it is possible that the agent may become blocked when performing output as the test client may not be able to process the output as quickly as required.

The data channel is configured with the Agent element in the configuration file, serviceconfig.xml.

Modifying the Agent element in the configuration file

Locate the serviceconfig.xml configuration file. See the related task.
Open it in an editor, and search for the Agent element.
Modify the value of the dataChannelSize attribute.
For example,
To specify that a data channel of 64 megabytes is to be used when the Java Profiling Agent is actively profiling, change the value of the dataChannelSize attribute to 64 MB. <Agent name="Java Profiling Agent" type="Profiler" dataChannelSize="64MB"> </Agent>

The following information applies to Linux. On Linux, the maximum data channel size is limited by the maximum shared memory size of the system. This configuration setting is located in /proc/sys/kernel/shmmax. The data channel will fail to be created if the dataChannelSize attribute value is greater than that specified in the /proc/sys/kernel/shmmax.

The following information applies to Solaris. On Solaris, the maximum data channel size is limited by the shared memory size of the system. The configuration setting is located in /etc/system under the shmmax attribute. The data channel will not be created if the dataChannelSize attribute value is greater than the shmmax attribute specified in the /etc/system. If that attribute does not exist, its value is assumed to be 1 MB, by default.

The following information applies to HP-UX. On HP-UX, the maximum data channel size is limited by the shared memory size of the system. The configuration setting is located in /etc/conf/master.d/core-hpux under the shmmax attribute. The data channel will not be created if the dataChannelSize attribute value is greater than the shmmax attribute specified in /etc/conf/master.d/core-hpux. If that file or attribute does not exist, its value is assumed to be 64 MB, by default.

The following information applies to AIX. On AIX, the maximum data channel size is limited by the maximum shared memory size of the system, which is fixed at 256 MB. The data channel will not be created if the dataChannelSize attribute value is greater than 256 MB.