What does the Taskpool Capacity Exceeded warning mean?

In some circumstances, while attempting to play a test composition the user will encounter a "Taskpool Capacity Exceeded" warning. This warning—users should note the distinction between warning and error here—indicates that the number of threads that the Composition requires exceeds the actual number of threads available in the taskpool. The default max value is 4096 threads per Maestro.

The "Taskpool Capacity Exceeded"' warning can occur in a Composition whose number of virtual users per server and/or Pages with lots of resources—anything that causes parallelism—exceeds the default value of 4096 threads per server.

Receiving this warning does not stop composition execution, but rather indicates a less than ideal configuration (e.g. ignoring it may slow composition execution to some extent because composition tasks must wait for an available thread).

While the task pool can be adjusted via the Central > Servers list in the lower panel Settings tab's "Pool.MaxWorkerCount" service setting, users should note that changing the default value will affect all Compositions that use the given server. For that reason, whenever this warning is received, testers may want to add a server(s) to the Composition rather than trying to increase the taskpool per server.