Difference between revisions of "Micro-threading"
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==Introduction== | ==Introduction== | ||
| − | + | There are some situations where applications need to execute lots of asynchronous concurrent operations. OS-level threads could be used for this purpose but an application can create only a limited count of threads. In matter of CPU utilization there are no significant performance gain if more threads is created then physical cores CPU have. In fact threads could be used for parallel processing on a multicore CPU and for writing more readable code. OS-level threads should be used mainly used for parallelism and better CPU utilization. If a programmer needs to write code which will be called asynchronously, then OS-level threads will be rather expensive in perspective of system resources. | |
| − | There are some situations where applications | ||
| − | |||
===CPU context switching methods=== | ===CPU context switching methods=== | ||
| − | |||
* Cooperative (use of explicit Yield call) | * Cooperative (use of explicit Yield call) | ||
* Preemptive (periodic timer based) | * Preemptive (periodic timer based) | ||
| Line 11: | Line 8: | ||
===Objectives=== | ===Objectives=== | ||
| − | |||
* Unlimited number of instances (limited by available memory) | * Unlimited number of instances (limited by available memory) | ||
* Fast switching, creation, destruction | * Fast switching, creation, destruction | ||
| Line 19: | Line 15: | ||
* Priority control | * Priority control | ||
* Support for view list of all microthreads | * Support for view list of all microthreads | ||
| − | |||
| − | |||
==Implementation== | ==Implementation== | ||
| − | |||
* [http://svn.zdechov.net/svn/PascalClassLibrary/MicroThreading/ MicroThreading] - Lazarus package, functional yet not finished, not multi-platform, need patching FPC | * [http://svn.zdechov.net/svn/PascalClassLibrary/MicroThreading/ MicroThreading] - Lazarus package, functional yet not finished, not multi-platform, need patching FPC | ||
| − | |||
==External links== | ==External links== | ||
| − | |||
* [http://santonov.blogspot.com/2007/10/yield-you.html C# Yield implementation in Delphi] | * [http://santonov.blogspot.com/2007/10/yield-you.html C# Yield implementation in Delphi] | ||
* [http://www.festra.com/wwwboard/messages/12899.html Cool little Coroutines function (Much better version)] | * [http://www.festra.com/wwwboard/messages/12899.html Cool little Coroutines function (Much better version)] | ||
* [http://msdn.microsoft.com/en-us/library/ms682661%28v=vs.85%29.aspx Fibers(Windows)] | * [http://msdn.microsoft.com/en-us/library/ms682661%28v=vs.85%29.aspx Fibers(Windows)] | ||
* [https://code.google.com/p/meaop/source/browse/trunk/MeObjects/src/uMeCoroutine.pas MeSDK Delphi coroutine implementation] | * [https://code.google.com/p/meaop/source/browse/trunk/MeObjects/src/uMeCoroutine.pas MeSDK Delphi coroutine implementation] | ||
| − | |||
[[Category:Parallel programming]] | [[Category:Parallel programming]] | ||
[[Category:Multitasking]] | [[Category:Multitasking]] | ||
Revision as of 00:07, 1 November 2016
Introduction
There are some situations where applications need to execute lots of asynchronous concurrent operations. OS-level threads could be used for this purpose but an application can create only a limited count of threads. In matter of CPU utilization there are no significant performance gain if more threads is created then physical cores CPU have. In fact threads could be used for parallel processing on a multicore CPU and for writing more readable code. OS-level threads should be used mainly used for parallelism and better CPU utilization. If a programmer needs to write code which will be called asynchronously, then OS-level threads will be rather expensive in perspective of system resources.
CPU context switching methods
- Cooperative (use of explicit Yield call)
- Preemptive (periodic timer based)
- Combined
Objectives
- Unlimited number of instances (limited by available memory)
- Fast switching, creation, destruction
- Automatic thread pool management by physical CPU core count
- Ability to run in main loop only (without TThread instances)
- Provide own synchronization tools (Yield, Sleep, CriticalSection, Semaphore, Mutex, WaitForMultipleObjects, Queues, Synchronize, ...)
- Priority control
- Support for view list of all microthreads
Implementation
- MicroThreading - Lazarus package, functional yet not finished, not multi-platform, need patching FPC
