Slides from my talk on TPL DataFlow given at the 33rd meeting of the Spbalt.net user group.

1. Dmitri Nesteruk
dmitrinesteruk@gmail.com

2. A publishes an event
B subscribes to the event
If lifetime of B < lifetime of A
We can get a memory leak
Weak event pattern

3. Library for composing async/event-based
programs
Event subscription wrapped as IDisposable
Lets you manually unsubscribe
Unsubscription automatic when source runs out
of data to supply

4. Declarative subscriptions
Pub/sub mechanism
Objects not aware of each other
Typically built on top of a DI container
Each component references the broker

5. Erlang
F# MailboxProcessor
Axum (dead)
Task Parallel Library (TPL) DataFlow
A library approach 

6. Fine-grained
Data-level (SIMD) – not in .NET
Autoparallelization
Coarse-grained
Using threads
Weird synchronization primitives (e.g. Pulse&Wait)
TPL DataFlow

7. A directed graph of data
Message passing
Buffering
Parallel execution
Dependency management

8. Pipeline
read
process
Network
read
process
write
process
collate
prepare
process
write

9. Input
Propagate
Calculate
indices
Output
Render to
screen
Save to DB
Read stock
market data
Filter
Save to DB

10. ISourceBlock<T>
Source of data; read
ITargetBlock<T>
Where you write the data to
IPropagatorBlock<TIn,TOut>
Propagator; performs data processing/filtering
As with Rx, ready-made implementations
provided

11. TransformBlock
Transforms data
Also: TransformManyBlock
ActionBlock
Processes the data

12. Post()
Sends a piece of data to the block for processing
LinkTo ()
Links a block with the next block in the graph
Takes an optional predicate
Returns an Idisposable
CancelationTokenSource if you change your
mind

13. Basic block processing

14. BatchBlock<T>
Combines sets of blocks into an array
JoinBlock<2> and <3>
Collects 2 or 3 inputs into a Tuple<2/3>
BatchJoinBlock
Merger of the above
Collects Tuple<IList<T>,…>

15. Provides a data storage buffer
Can be used synchronously
block.Post()
block.Receive()
or asynchronously
await block.SendAsync()
Await block.ReceiveAsync()

16. Grouping Blocks

17. Not a competitor to Rx or TPL itself
Course-grained parallelization/sequencing
mechanism
‘Cheap’ multithreading

18. Questions?

19. Конференция по .NET технологиям
4 апреля 2014, ПетроКонгресс
http://dotnext.ru
Предлагайте доклады 