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. As for CPU utilization there is no significant performance gain if more threads are created than physical cores available on a CPU. 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) | ||
* Combined | * Combined | ||
===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 | ||
* Automatic thread pool management by physical CPU core count | * Automatic thread pool management by physical CPU core count | ||
| − | * Ability to run in main loop only (without TThread instances) | + | * Ability to run in main loop only (without [[TThread]] instances) |
* Provide own synchronization tools (Yield, Sleep, CriticalSection, Semaphore, Mutex, WaitForMultipleObjects, Queues, Synchronize, ...) | * Provide own synchronization tools (Yield, Sleep, CriticalSection, Semaphore, Mutex, WaitForMultipleObjects, Queues, Synchronize, ...) | ||
* Priority control | * Priority control | ||
* Support for view list of all microthreads | * Support for view list of all microthreads | ||
| + | ====Supported platforms==== | ||
| + | * Supported platforms are 32-bit Windows and Linux | ||
==Implementation== | ==Implementation== | ||
| − | + | * [http://svn.zdechov.net/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] | ||
| − | + | [[Category:Parallel programming]] | |
[[Category:Multitasking]] | [[Category:Multitasking]] | ||
Revision as of 05:31, 27 March 2020
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. As for CPU utilization there is no significant performance gain if more threads are created than physical cores available on a CPU. 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
Supported platforms
- Supported platforms are 32-bit Windows and Linux
Implementation
- MicroThreading - Lazarus package, functional yet not finished, not multi-platform, need patching FPC
