ETW Events in Task Parallel Library and PLINQ

Both the Task Parallel Library and PLINQ generate Event Trace for Windows (ETW) events that you can use to profile and troubleshoot applications by using tools such as the Windows Performance Analyzer. However, in most scenarios, the best way to profile parallel application code is to use the Concurrency Visualizer in Visual Studio Ultimate.

Task Parallel Library ETW Events

In the EVENT_HEADER structure, the ProviderId GUID for events generated by ParallelFor(), ParallelForEach() and ParallelInvoke() is:

0x2e5dba47, 0xa3d2, 0x4d16, 0x8e, 0xe0, 0x66, 0x71, 0xff, 0xdc, 0xd7, 0xb5

Parallel Loop Begin

EVENT_DESCRIPTOR.Task = 1

EVENT_DESCRIPTOR.Id = 1

User Data

Name	Type	Description
OriginatingTaskSchedulerID	System.Int32	The ID of the TaskScheduler that started the loop.
OriginatingTaskID	System.Int32	The ID of the task that started the loop.
ForkJoinContextID	System.Int32	A unique identifier used to indicate nesting and pairs for events with fork/join semantics.
OperationType	System.Int32	Indicates the type of loop: 1 = ParallelInvoke 2 = ParallelFor 3 = ParallelForEach
InclusiveFrom	System.Int64	The starting value of the loop counter
ExclusiveTo	System.Int64	The ending value of the loop counter

Parallel Loop End

EVENT_DESCRIPTOR.Task = 2

EVENT_DESCRIPTOR.Id = 2

User Data

Name	Type	Description
OriginatingTaskSchedulerID	System.Int32	The ID of the TaskScheduler that started the loop.
OriginatingTaskID	System.Int32	The ID of the task that started the loop.
ForkJoinContextID	System.Int32	A unique identifier used to indicate nesting and pairs for events with fork/join semantics.
totalIterations	System.Int64	The total number of iterations

Parallel Invoke Begin

EVENT_DESCRIPTOR.Task = 3

EVENT_DESCRIPTOR.Id = 3

User Data

Name	Type	Description
OriginatingTaskSchedulerID	System.Int32	The ID of the TaskScheduler that started the loop.
OriginatingTaskID	System.Int32	The ID of the task that started the loop.
ForkJoinContextID	System.Int32	A unique identifier used to indicate nesting and pairs for events with fork/join semantics.
totalIterations	System.Int64	The total number of iterations
operationType	System.Int32	Indicates the type of loop: 1 = ParallelInvoke 2 = ParallelFor 3 = ParallelForEach
ActionCount	System.Int32	The number of actions that will be executed in the parallel invoke.

Parallel Invoke End

EVENT_DESCRIPTOR.Task = 4

EVENT_DESCRIPTOR.Id = 4

User Data

Name	Type	Description
OriginatingTaskSchedulerID	System.Int32	The ID of the TaskScheduler that started the loop.
OriginatingTaskID	System.Int32	The ID of the task that started the loop.
ForkJoinContextID	System.Int32	A unique identifier used to indicate nesting and pairs for events with fork/join semantics.

PLINQ ETW Events

The EVENT_HEADER.ProviderId GUID for PLINQ is:

0x159eeeec, 0x4a14, 0x4418, 0xa8, 0xfe, 0xfa, 0xab, 0xcd, 0x98, 0x78, 0x87

Parallel Query Begin

EVENT_DESCRIPTOR.Task = 1

EVENT_DESCRIPTOR.Id = 1

User Data

Name	Type	Description
OriginatingTaskSchedulerID	System.Int32	The ID of the TaskScheduler that started the loop.
OriginatingTaskID	System.Int32	The ID of the task that started the loop.
QueryID	System.Int32	A unique query identifier.

Parallel Query End

EVENT_DESCRIPTOR.Task = 2

EVENT_DESCRIPTOR.Id = 2

User Data

Name	Type	Description
OriginatingTaskSchedulerID	System.Int32	The ID of the TaskScheduler that started the loop.
OriginatingTaskID	System.Int32	The ID of the task that started the loop.
QueryID	System.Int32	A unique query identifier.

See Also

Concepts

Task Parallel Library

Parallel LINQ (PLINQ)

Other Resources

ETW Events in the .NET Framework