Re: [Boost-users] Does anybody interested in active object

Subject: Re: [Boost-users] Does anybody interested in active object
From: Marat Abrarov (abrarov_at_[hidden])
Date: 2010-11-07 18:11:57

To Dean Michael Berris:
> You'd be better of doing data parallelism with Boost.MPI

No. Because I'm speaking about thread-based parallelism (with shared memory
access).
Processed-based parallelism and IPC supplement 
but don't replace thread-based parallelism in general.

> and/or Boost.Asio's io_service
> run on multiple threads, and having independent tasks multiplexed
> across a number of processors (either through processes or threads)

Tie this tasks with the data they share and You will have an active object.
If the tasks don't have shared data - they don't need an active object.
I think - active object is built on task-based parallelism 
but it does not mean that "active object" should replace 
"task-based parallelism" everywhere.

> But what you're describing is not the active object pattern. ;)

http://en.wikipedia.org/wiki/Active_object
http://en.wikipedia.org/wiki/Active_object_(Symbian_OS)
What about ma::echo::server::session class - is it an active object?

http://www.boost.org/doc/libs/1_44_0/doc/html/boost_asio/example/chat/chat_c
lient.cpp 
Is chat_client an active object? If "yes" then why?
chat_client::write have no completion callback - and this is not enough
sometimes 
(I can say "always", if You don't implementing "fire-and-forget" logic which
is rather seldom).

http://www.boost.org/doc/libs/1_44_0/doc/html/boost_asio/example/serializati
on/connection.hpp
s11n_example::connection is an active object and have completion callback...
but it's much simpler then ma::echo::server::session_manager - I try to
suggest "samples" that can help
to build such a kind of complex active objects.

http://www.drdobbs.com/go-parallel/blog/archives/2009/09/parallelism_sho.htm
l
> We are surrounded by parallelism even more so that serial activities. 
> Social and biological systems are immersed in parallelism and these 
> systems have worked out the kinks over millions of years. 
> In biological systems, independent units perform simple computations 
> or activities independently and in parallel.
and
> IMPLICATIONS FOR COMPLEX REALTIME SYSTEMS:
> Complex real-time systems would be a sea of state machine objects 
> interacting with each other. There will be low level state machines 
> which would work together to implement high level state machine behavior.

Here's the place for active object pattern.

Thanks for that attention that you have given to my question.
Marat Abrarov.

> -----Original Message-----
> Date: Sun, 7 Nov 2010 12:58:06 +0800
> From: Dean Michael Berris <mikhailberis_at_[hidden]>
> To: boost-users_at_[hidden]
> Subject: Re: [Boost-users] Does anybody interested in active object
> 	pattern?
> Message-ID:
> 	<AANLkTi=PTkqO2ngdYcNNbp12hNnS=8=PxK3YsccajpFV_at_[hidden]>
> Content-Type: text/plain; charset=UTF-8
> 
> On Sat, Nov 6, 2010 at 10:56 PM, Marat Abrarov <abrarov_at_[hidden]> wrote:
> >
> > Does anybody interested in active object pattern for massive parallelism
> by means of C++? (Intel TBB doesn't offer a
> > similar approach)
> >
> 
> I'm not sure how you think active objects help for massive parallelism
> because the active object pattern implies that you're serializing
> operations on a single object.
> 
> I've used Boost.Asio to implement Active Objects but only in cases
> where it makes sense -- like for example a concurrent accumulator or a
> concurrent resource handle (log sink for example). You'd be better of
> doing data parallelism with Boost.MPI and/or Boost.Asio's io_service
> run on multiple threads, and having independent tasks multiplexed
> across a number of processors (either through processes or threads).
> 
> I remember reading about Microsoft's efforts (through Herb Sutter) to
> introduce an "active" extension to Microsoft Visual C++, where you can
> easily make classes that instantiate to active objects. I'm not sure
> where that effort is now though.
> 
> HTH
> 
> --
> Dean Michael Berris
> deanberris.com
>