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. | + | 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 multi-core CPU and for writing more readable code. OS-level threads should be 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=== | ===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 | ||
| Line 11: | Line 11: | ||
* 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 | ||
| − | == | + | ==Implementations== |
| − | * [http://svn.zdechov.net | + | * [http://svn.zdechov.net/PascalClassLibrary/MicroThreading/ MicroThreading] - Lazarus package, functional yet not finished, not multi-platform, needs patching the Free Pascal |
| + | * [[STAX]] - Single Threaded Asynchronous EXecution framework (STAX for short) enables async/await style co-routines for Free Pascal | ||
==External links== | ==External links== | ||
Latest revision as of 19:51, 31 August 2021
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 multi-core CPU and for writing more readable code. OS-level threads should be 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
Implementations
- MicroThreading - Lazarus package, functional yet not finished, not multi-platform, needs patching the Free Pascal
- STAX - Single Threaded Asynchronous EXecution framework (STAX for short) enables async/await style co-routines for Free Pascal
