Multi-Threading using NSOperation

Transcript

1. Multi - Threading by zeeshan 1
2. CPU Why do we have n number of Core(s)? 2
3. nothing is limitless & every problem has a solution Clock Speed A time unit 3
4. Thread ‘Kernel-level’ + ‘Application-level’ Data Structures An application can use multiple cores by creating multiple threads. 4 Parallel Computation Asynchronous Solution
5. Key Terms • Process • Thread (Safe / Un-Safe) • Task • Concurrent / Non-Concurrent • Concurrent vs Parallel 5
6. NSThread POSIX (Mavericks is 100% POSIX conferment) 6 Life Cycle
7. Hazard of Threaded Programming • UIKit access • Database access • Stale result • Cancellation • De-allocation 7
8. Solutions • Operations (Current Session) • GCD (Next Session) • Notification Queue • Asynchronous (Hopefully Next to Next Session) • Timers 8
9. NS Operation to the rescue 9
10. NS Operations • Manage all threaded code • Model asynchronous operations • KVO Support • Dependencies • Priorities 10
11. NS Operation II • Thread Confinement • Completion Block • Cancellation • Concurrent vs Non-Concurrent • Some Caveats... 11
12. NS Operation Queue • Simpler, Name it • Add, Ready & Execute, Cancel | Finish • Pending Operations • Multiple Queues • Threads & Queues 12
13. NS Operations Queue II • Queue Width • Pause (Suspended) Queues • Cancellation • KVC Compliant • Add Operation with Blocks 13
14. NS Operations - Use • Blocks • Concrete sub classes • Selector • Block • User defined sub classes 14
15. References: • Multithreading Using NSOperation (http:// izeeshan.wordpress.com/2014/08/17/multi-threading- using-nsoperation/) • Concurrency Programming Guide • Threading Programming Guide • API References 15
16. Any Questions? Thank you! @zeeshan_khan http://izeeshan.wordpress.com/ 16
17. 17 @zeeshan_khan