An efficient Threadpool engine with priorities that scales very well
An efficient Threadpool engine with priorities that scales very well
version 3.2
Author: Amine Moulay Ramdane
Description:
Efficient Thread Pool Engine with priorities that scales very well. I have updated my efficient Threadpool engine with priorities and my Threadpool engine to version 3.2, i have come up with a new algorithm that is more optimized and that scales very well.
The following have been added to my efficient Threadpool engine:
- I have used scalable counting networks to make my Threadpool engine scales very well.
- You can give the following priorities to jobs:
LOW_PRIORITY
NORMAL_PRIORITY
HIGH_PRIORITY
- The worker threads enter in a wait state when there is no job in the concurrent FIFO queues - for more efficiency -
- You can distribute your jobs to the worker threads and call any method with the threadpool's execute() method.
- It uses work-stealing to be more efficient.
- You can configure it to use stacks or FIFO queues , when you use stacks it will be cache efficient.
- Now it can use processor groups on windows, so that it can use more than 64 logical processors and it scales well.
- Now it distributes the jobs on multiple FIFO queues or stacks so that it scales well.
- You can wait for the jobs to finish with the wait() method.
- It's NUMA-aware and NUMA efficient.
- And it is portable to many operating systems.
- Uses O(1) complexity on enqueue and O(3) worst case complexity on dequeue.
And look at the ThreadPoolExecutor Class of Java, look for example at the awaitTermination() method, it says:
---
boolean awaitTermination(long timeout, TimeUnit unit)
Blocks until all tasks have completed execution after a shutdown request, or the timeout occurs, or the current thread is interrupted, whichever happens first.
--
read more here:
https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/ThreadPoolExecutor.html#method.summary
Did you notice ?
In Java when you wait for the tasks you have to wait for "ALL" the tasks, and that's not efficient , and if you want to use the object from multiple threads i think it will have the same effect, you can avoid some of the problems by using many objects of the ThreadPoolExecutor class but this will take ressources and this will cause more and more context switches and that's bad, i think C# has the same problem, other than that Java and C# don't support priorities, it means that you can not give priorities to tasks/jobs, like high or normal or low, and that's not good for games and other applications where you have to use priorities even if the system is not a realtime system, this is why i have decided to implement my efficient Threadpool engine version 3.2 that supports those characteristics and that scales well, so that you can create
a child object of the Threadpool class that will use the same
worker threads and that will wait only for the tasks that you will add with the execute() method , and also my efficient Threadpool engine supports 3 priorities, High and normal and low, that's where my efficient Threadpool engine comes in hand and that's where it's efficient. Hope you will like it.
Please read the HTML tutorial inside the zip.
More precision about my efficient Threadpool that scales very well, my Threadpool is much more scalable than the one of Microsoft, in the workers side i am using scalable counting networks to distribute on the many queues or stacks, so it is scalable on the workers side, on the consumers side i am also using lock striping to be able to scale very well, so it is scalable on those parts, on the other part that is work stealing, i am using scalable counting networks, so globally it scales very well, and since work stealing is "rare" so i think that my efficient Threadpool that scales very well is really powerful, and it is much more optimized and the scalable counting networks eliminate false sharing, and it works with Windows and Linux.
You have to know that to enlarge the stack of the worker threads of the Threadpool that use TThread, you have to set the stack size for the executable.
Look into defines.inc there is many options:
{$DEFINE CPU32} and {$DEFINE Windows32} for 32 bit systems
{$DEFINE CPU64} and {$DEFINE Windows64} for 64 bit systems
Look at test.pas demo inside the zip file...
Language: FPC Pascal v2.2.0+ / Delphi 5+: http://www.freepascal.org/
Operating Systems: Win , Linux and Mac (x86).
Required FPC switches: -O3 -Sd -dFPC -dWin32 -dFreePascal
-Sd for delphi mode....
Required Delphi switches: -DDelphi -DMSWINDOWS -$H+
For Delphi XE-XE7 use the -DXE switch
{$DEFINE CPU32} and {$DEFINE Windows32} for 32 bit systems
{$DEFINE CPU64} and {$DEFINE Windows64} for 64 bit systems
Please click on the small arrow on the right of the zip file bellow to download...