From the .Net Guide I see this :
The .NET agent property, perfmon.metric.filterPattern, specifies the Performance Monitor counters the agent reads. The default setting is:
The filter follows the format |Object|Instance|Counter or |Object|Counter (if there is no instance) where:
■ Object identifies a performance monitor category, such as Memory, Processor, or Process.
■ Instance identifies a specific instance of the specified object. Some objects, such as Memory, do not have instances.
■ Counter identifies the specific type of metric for the Object|Instance to be collected. For example, the .NET CLR Memory Performance Monitor object has counters such as # Bytes in all heaps, Gen 0 heap size, # GC handles, and % time in GC.
The default filter also includes the {osprocessname} placeholder. In the Investigator, the {osprocessname} placeholder is replaced to identify the instances of the standalone applications monitored or the application pool name for the IIS worker process, for example w3wp(BusinessServiceAppPool)