This slides are for the Parallel Computing talk. You can read the repo samples of the talk @ https://github.com/pablomolnar/gpars_samples @pmolnar

1. Parallel Computing
(with GPars)
NOV 2011

2. Evolution
● Old Days
○ threads
○ synchronize
○ locks
○ wait-notify

3. Evolution
● Recent enhancements
○ java.util.concurrent.*
○ Future task
○ Executor Pools
○ Blocking Queues
○ ConcurrentMap

4. Evolution
● Emerging Technologies
○ Map-Reduce
○ API's (Google Collections, JSR-166)
○ Non-blocking I/O
○ Parallel Friendly Languages (Scala, Clojure, Groovy)

5. Groovy Parallel Systems
High level abstractions for writing concurrent code!
● Code-level Helpers
○ Parallel Collections
○ Asynchronous Processing
○ Fork/Join - Map/Reduce
● Architecture-level Concepts
○ Dataflows
○ Actors
● Protecting Shared Mutable State
○ Agents

6. Groovy Parallel Systems
High level abstractions for writing concurrent code!
● Code-level Helpers
○ Parallel Collections
○ Asynchronous Processing
○ Fork/Join - Map/Reduce
● Architecture-level Concepts
○ Dataflows
○ Actors (For next time...)
● Protecting Shared Mutable State
○ Agents (For next time...)

7. DEMO 1
(Parallel encryption)

8. Optimal Thread Pool Size
Pool size = ???

9. Optimal Thread Pool Size
Pool size = Ncores

10. Optimal Thread Pool Size
Pool size = Ncores + 1

11. Optimal Thread Pool Size
Pool size = Ncores + Block. Op. Ratio

12. Optimal Thread Pool Size
Pool size = Ncores + wait time
cpu time

13. DEMO 2
"Dado un rango obtener la cantidad de
nr. primos agrupados por él ultimo digito"

14. Danger
Don't mess up with mutable shared data!

15. DEMO 3
(Facebook Search)

16. Collections
● eachParallel()
● eachWithIndexParallel()
● collectParallel()
● findAllParallel()
● findAnyParallel
● findParallel()
● everyParallel()
● anyParallel()
● grepParallel()
● groupByParallel()
● foldParallel()
● minParallel()
● maxParallel()
● sumParallel()
● splitParallel()
● countParallel()
● foldParallel()

17. DEMO 4
(Facebook Singles)

18. Fork-Join
Map-Reduce

19. DEMO 5
(API Calls)

20. DEMO 6
(Multiget)

21. Multiget

22. + Info
● http://gpars.org/0.12/guide/guide/single.html
● http://www.slideshare.net/paulk_asert/concurrency-with-
gpars
● http://gee.cs.oswego.edu/dl/papers/fj.pdf
● http://static.googleusercontent.
com/external_content/untrusted_dlcp/labs.google.
com/en/us/papers/mapreduce-osdi04.pdf
● Java Concurrency in Practice (ISBN-0321349601)
Pics Credits
● Stone age: http://tinyurl.com/bvnlv74
● Steam train: http://tinyurl.com/6lp3krq
● Speed train: http://tinyurl.com/7jjc3v5
● CPU: http://www.flickr.com/photos/olivander/149865626/

23. https://github.com/pablomolnar/gpars_samples
@pmolnar