January 29, 2007
DCSP is a lightweight concurrency library that I wrote last summer. While most threading libraries seek to avoid concurrency or eliminate it entirely, DCSP takes a slightly different approach.  The idea grew from the work I did on StackThreads and is inspired by C.A.R. Hoare's Communicating Sequential Processes and Robin Milner's Pi-Calculus.  In DCSP, concurrency is the essential feature of program design.  This is not as absurd as it initially sounds, since many programs are innately concurrent.

A DCSP program is composed of a network of communicating processes, each connected by synchronous point-to-point channels.  This idea is easy to visualize like a large digital circuit.

The syntax is closer to Occam, and is far simpler than JCSP. Additionally, the performance of DCSP far surpasses JCSP, and unlike C++CSP, DCSP is actually multi-threaded.

The current version supports two schedulers, one cooperative scheduler based on stack threads, and another threaded scheduler using Phobos' threads.  In the future, these may be supplemented with a hybrid scheduler using a work-stealing algorithm similar to MIT's CiLK project. 
 Additionally, the basic ideas in this project could be extended to network communication.

Anyway, you can check out the library at: http://www.assertfalse.com

JCSP: http://www.cs.kent.ac.uk/projects/ofa/jcsp/
C++CSP: http://www.twistedsquare.com/cppcsp/
Occam: http://www.wotug.org/occam/
Communicating Sequential Processes: http://www.usingcsp.com/cspbook.pdf

-Mik
January 29, 2007
On Sun, 28 Jan 2007 23:50:24 -0500, Mikola Lysenko wrote:

> DCSP is a lightweight concurrency library that I wrote last summer. While most threading libraries seek to avoid concurrency or eliminate it entirely, DCSP takes a slightly different approach.  The idea grew from the work I did on StackThreads and is inspired by C.A.R. Hoare's Communicating Sequential Processes and Robin Milner's Pi-Calculus.  In DCSP, concurrency is the essential feature of program design.  This is not as absurd as it initially sounds, since many programs are innately concurrent.
> 
> A DCSP program is composed of a network of communicating processes, each connected by synchronous point-to-point channels.  This idea is easy to visualize like a large digital circuit.
> 
> The syntax is closer to Occam, and is far simpler than JCSP. Additionally, the performance of DCSP far surpasses JCSP, and unlike C++CSP, DCSP is actually multi-threaded.
> 
> The current version supports two schedulers, one cooperative scheduler
> based on stack threads, and another threaded scheduler using Phobos'
> threads.  In the future, these may be supplemented with a hybrid
> scheduler using a work-stealing algorithm similar to MIT's CiLK project.
>   Additionally, the basic ideas in this project could be extended to
> network communication.
> 
> Anyway, you can check out the library at: http://www.assertfalse.com
> 
> JCSP: http://www.cs.kent.ac.uk/projects/ofa/jcsp/
> C++CSP: http://www.twistedsquare.com/cppcsp/
> Occam: http://www.wotug.org/occam/
> Communicating Sequential Processes: http://www.usingcsp.com/cspbook.pdf
> 
> -Mik


Nice work, Mik!  Thanks for contributing this.   I think there may be some valuable applications for D and CSP.  It might be fun to try using it with games/graphic software -- perhaps using the cooperative scheduler initially.

It's certainly an opportunity to showcase concurreny theory implementations in D.

Thanks much!

-JJR
January 29, 2007
Mikola Lysenko wrote:
> DCSP is a lightweight concurrency library that I wrote last summer. While most threading libraries seek to avoid concurrency or eliminate it entirely, DCSP takes a slightly different approach.  The idea grew from the work I did on StackThreads and is inspired by C.A.R. Hoare's Communicating Sequential Processes and Robin Milner's Pi-Calculus.  In DCSP, concurrency is the essential feature of program design.  This is not as absurd as it initially sounds, since many programs are innately concurrent.
> 
> A DCSP program is composed of a network of communicating processes, each connected by synchronous point-to-point channels.  This idea is easy to visualize like a large digital circuit.
> 
> The syntax is closer to Occam, and is far simpler than JCSP. Additionally, the performance of DCSP far surpasses JCSP, and unlike C++CSP, DCSP is actually multi-threaded.
> 
> The current version supports two schedulers, one cooperative scheduler based on stack threads, and another threaded scheduler using Phobos' threads.  In the future, these may be supplemented with a hybrid scheduler using a work-stealing algorithm similar to MIT's CiLK project. 
>  Additionally, the basic ideas in this project could be extended to network communication.
> 
> Anyway, you can check out the library at: http://www.assertfalse.com
> 
> JCSP: http://www.cs.kent.ac.uk/projects/ofa/jcsp/
> C++CSP: http://www.twistedsquare.com/cppcsp/
> Occam: http://www.wotug.org/occam/
> Communicating Sequential Processes: http://www.usingcsp.com/cspbook.pdf
> 
> -Mik

Excellent.  I spent some time programming Inmos Transputers using Occam back in the day.

But I have to say the project of yours that I think really deserves more attention is *Professor Automaton's Cruel Legume Device*.
     http://www.assertfalse.com/puyo/www/
:-)
Burned many hours on puyo puyo back in the day too. :-)  *DAI DAGEKI!*

--bb
January 29, 2007
Bill Baxter wrote:
> Mikola Lysenko wrote:
> 
>> DCSP is a lightweight concurrency library that I wrote last summer. While most threading libraries seek to avoid concurrency or eliminate it entirely, DCSP takes a slightly different approach.  The idea grew from the work I did on StackThreads and is inspired by C.A.R. Hoare's Communicating Sequential Processes and Robin Milner's Pi-Calculus.  In DCSP, concurrency is the essential feature of program design.  This is not as absurd as it initially sounds, since many programs are innately concurrent.
>>
>> A DCSP program is composed of a network of communicating processes, each connected by synchronous point-to-point channels.  This idea is easy to visualize like a large digital circuit.
>>
>> The syntax is closer to Occam, and is far simpler than JCSP. Additionally, the performance of DCSP far surpasses JCSP, and unlike C++CSP, DCSP is actually multi-threaded.
>>
>> The current version supports two schedulers, one cooperative scheduler based on stack threads, and another threaded scheduler using Phobos' threads.  In the future, these may be supplemented with a hybrid scheduler using a work-stealing algorithm similar to MIT's CiLK project.  Additionally, the basic ideas in this project could be extended to network communication.
>>
>> Anyway, you can check out the library at: http://www.assertfalse.com
>>
>> JCSP: http://www.cs.kent.ac.uk/projects/ofa/jcsp/
>> C++CSP: http://www.twistedsquare.com/cppcsp/
>> Occam: http://www.wotug.org/occam/
>> Communicating Sequential Processes: http://www.usingcsp.com/cspbook.pdf
>>
>> -Mik
> 
> 
> Excellent.  I spent some time programming Inmos Transputers using Occam back in the day.

Sweet! Me too <g>

DCSP has been a long time coming, and it's nice to see such a succinct syntax (quite unlike the C++ and Java attempts). Great job, Mik!

> 
> But I have to say the project of yours that I think really deserves more attention is *Professor Automaton's Cruel Legume Device*.
>      http://www.assertfalse.com/puyo/www/
> :-)
> Burned many hours on puyo puyo back in the day too. :-)  *DAI DAGEKI!*

Too cruel for me -- I was wasting time on the original Mac FlightSim <g>

> 
> --bb
January 29, 2007
Mikola Lysenko Wrote:
> DCSP is a lightweight concurrency library that I wrote last summer.

Very nice. I was going to write something similar, but your solution with cooperative scheduler is very good. I will use it my projects, and eventually imeplement asynchronous channels (like in Erlang), and process exception linking.

One more time: good work.


January 31, 2007
Mikola Lysenko wrote:
> DCSP is a lightweight concurrency library that I wrote last summer. While most threading libraries seek to avoid concurrency or eliminate it entirely, DCSP takes a slightly different approach.  The idea grew from the work I did on StackThreads and is inspired by C.A.R. Hoare's Communicating Sequential Processes and Robin Milner's Pi-Calculus.  In DCSP, concurrency is the essential feature of program design.  This is not as absurd as it initially sounds, since many programs are innately concurrent.

Have you used Plan 9’s threading libraries at all (on Plan 9 or ported to UNIX) or Inferno/Limbo threading?  Can you compare the models?

--Joel
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