Asp Forum - Effiicient Threadpool engine with priorities version 2.4

Ramine

11/21/2015 1:00:00 AM

Hello,

I have updated my efficient Threadpool engine with priorities to version
2.4, in this new algorithm i have reduced more the serial part of the
Amdahl equation so that it can scale more, and i have corrected a bug ,
and i have thoroughly tested it and i think that it's fast and stable
now, also i have optimized my algorithm more by aligning some records so
that it optimize the cache-line transfers... so hope that you will be
happy with this new algorithm.

You can reaD about it and download it from:

https://sites.google.com/site/aminer68/threadpool-with-...

Description:

Efficient Thread Pool Engine.

The following have been added:

- You can give the following priorities to jobs:

LOW_PRIORITY
NORMAL_PRIORITY
HIGH_PRIORITY

- Uses a fast concurrent FIFO queue that satisfies many requirements: it
is FIFO fair, it minimizes efficiently the cache-coherence traffic and
it is energy efficient on the pop(): when there is no items in the queue
it will not spin-wait , but it will wait on a portable manual event
object..

- Enters in a wait state when there is no job in the queue - for more
efficiency -

- You can distribute your jobs to the workers threads and call any
method with the threadpool's execute() method.

- You can wait for the jobs to finish with the wait() method.

- Uses O(1) complexity on enqueue and O(3) worst case complexity on dequeue.

I have updated my efficient Threadpool engine with priorities and my
Threadpool engine to version 2.4, i have come up with a new algorithm
that is more optimized, in this new algorithm i have reduced and
minimized the cache-line transfers so that the serial part of the Amdahl
law has been reduced by 2 times, hope that you will be happy with this
new efficient algorithm... i have also changed the concurrent FIFO queue
of my efficient Threadpool engine with priorities, now the concurrent
FIFO queue is fast, so it's really fast, so as you have noticed that
designing and implementing an efficient Threadpool engine as my
efficient Threadpool engine with priorities is somewhat a hard job, so
to facilitate the reasonning about concurrent programming i have also a
new efficient algorithm to facilitate the reasonning about
"correctness", and i think that now that my new algorithm has
facilitated the reasonning about correctness and now that i have tested
it thoroughly , you can be more confident cause i think that my new
algorithm of my efficient Threadpool engine with priorities is correct
and stable now and it is also very fast.

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#meth...

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 2.4
that supports those characteristics, 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 file to understand how to
use the execute() and wait() methods etc.

Look into defines.inc there is many options:

CPU32: for 32 bits architecture
CPU64: for 64 bits architecture

Please read the HTML tutorial inside the zip.

Look at test.pas demo inside the zip file...

Language: FPC Pascal v2.2.0+ / Delphi 5+: http://www.freep...

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

Note: testpool.pas is a parallel program of a Matrix multiply by a
vector that uses SSE+ and it requires Delphi 5+. test.pas and
test_thread.pas works with both FreePascal and Delphi.

Thank you,
Amine Moulay Ramdane.

comp.programming

Effiicient Threadpool engine with priorities version 2.4

Ramine

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