Introduction to TPL Dataflow: Document

Question

Hello,

I've same questions about the document Introduction to TPL Dataflow:

In chapter MaxMessagePerTask I found the following statement:
To address this, the MaxMessagesPerTask option exists.  It defaults to DataflowBlockOptions.Unbounded (-1), meaning that there is no maximum

It should be "It defaults to MaxMessagesPerTask = -1, ..", or?

In chapter MaxNumberOfGroups I found the following statement:
By default, the number of groups is DataflowBlockOptions.Unbounded (-1), but it may be explicitly set to a value greater than one.

It should be "By default, the number of groups is MaxNumberOfGroups = -1 ...", or?

In chapter MaxDegreeOfParallelism I found the following statement:
It defaults to 1, meaning only one thing may happen in a block at a time.  If set to a value higher than 1, that number of messages may be processed concurrently by the block.  If set to DataflowBlockOptions.Unbounded (-1), any number of messages may be processed concurrently, with the maximum automatically managed by the underlying scheduler targeted by the dataflow block.

It should be "If set to MaxDegreeOfParallelism  = -1, ", or?

Thanks in advance for clarification.

 

---

-

Answer 1

Hi Marc,

 

Thanks for evaluating TPL dataflow and furthermore reading the help doc!

 

This is an English language issue that I would not try to argue over. I’ll only explain what we’ve meant.

 

All of these options are of type Int32. Thus there is an Int32 value that has a special meaning. You’ve figured it – that special value is -1. However, we strongly recommend that you use the name constant DataflowBlockOptions.Unbounded to keep your code agnostic of the actual Int32 value.

 

Thus the text “It defaults to DataflowBlockOptions.Unbounded (-1)” should be read as “It defaults to DataflowBlockOptions.Unbounded which has the value of -1”.

 

 

Zlatko Michailov

Software Development Engineer, Parallel Computing Platform

Microsoft Corp.

---

This posting is provided "AS IS" with no warranties, and confers no rights.

Answer 2

Hi Zlatko,

thanks for clarification this point. Now I've got it. DataflowBlockOptions.Unbounded is "only" a constant. I missed the Options in DataflowBlockOptions and I thought  the Unbound(-1) (actually a const not a method) belongs to the BoundedCapacity Option.

---

-