User:Oleg Kobchenko/Threads

Assumptions

• One thread is one stack
• J instance is single-threaded
• A process can host multiple independent J instances
• Theoretically, J process could have multiple GUI message loops, one per thread; in reality only the master instance on main thread has the message loop; slave instances should use explicit wait to receive notifications or become inactive (exit execution) to be reused

Thread Control

• Create J instance
• Create thread: start execution or in suspended mode
  • populate slave instance with code names synchronously from master
  • initiate execution using callback allocated in slave
• Suspend / resume execution
• Destroy thread / exit execution

Synchronization

• Mutexes
• Locking
• WaitForMultipleObjects (win32)
• Common variables, mapped files

Notifications

• Conditional variables (pthreads)
• Events (win32)
• Polling, timer, explicit wait, irresponsive GUI
• Using message loop, faking GUI events
• SIGNALs, sockets

Examples

All files are placed under user/threads

• File:Wthreads.ijs - common API
• File:Callback.ijs - using J callback
• File:Multi1.ijs - multi threads single J instance
• File:Multi.ijs - multi threads multi J instances
• File:Multi3.ijs - multi threads multi J instances multi DLL

References

J::

• jasync
• Calling J.DLL, User Manual
• C-code to process J array
• Parallel Processing Help

Windows::

• Using Processes and Threads, MSDN
• Using Synchronization, MSDN
• Multiple Threads in the User Interface, MSDN

.NET::

• Guidelines for Asynchronous Programming, MSDN
• Asynchronous Programming Design Patterns, MSDN2
• Overview of .NET multithreading
• WinForms UI Thread Invokes, Justin Rogers
• Moving from the Desktop to Devices: Multithreading and the User Interface, MSDN
• Invoke vs BeginInvoke, Greg Young

POSIX Threads::

• Programming POSIX Threads, humanfactor.com
• Parallel Programming, AIX Programming
• PThread Programming, IBM
• pthreads Tutorial, LLN lab
• Multi-Threaded Programming
• Parallel Programming Theory, Notifications

Java::

• JNI Development on Mac OS X, Apple TN2147, Invoking JVM from a pthread
• Specific notification pattern, IBM Java
• Threads and Locks, Java Language Specification
• invokeLater