Charm++ parallel programming system

[Christian Perez <christian.perez AT inria.fr>]

Ok ... here are the ugly details:

We have a JAVA code that interprets an assembly of components, which in this case are implemented in Charm++.
The mainchare creates a second chare (called RT) that launched the JVM in an entry method start, which is
not threaded (I have problem with the JVM if it is not in the main thread :<)

The JAVA code needs to create/connect/execute components. Hence, the java code invokes JNI methods  to call C++ code.
The creation turns to be easy (it is a simple call to ckNew).
My current problem is with the 'connect'.

Logically, the connection operation should be as simple as:
    type_of_P p = component_a->get_ref_of_port_P()
    component_b->set_ref_of_port_U(p)

My current version is in term of ci file is:

    chare type_of_P { ... }

    chare Component_A : type_of_P {
        entry void get_ref_of_port_P(const CkCallbackResumeThread& cb) { m_si * m = new m_si(); m->ckid=thishandle; } // see def of m_si below
    }

    chare Component_B {
        entry [sync] void set_ref_of_port_U(CkChareID& ckid);

I am using a message to send back a reference to something of type_of_P

    message m_si {
        CkChareID ckid;
   }

And the implementation in the jni 'connect' method:

     m_si* m;
     component_A.get_ref_of_port_P(CkCallbackResumeThread((void*&)m));
     component_B.set_ref_of_port_u(m->ckid);


Thus, there are in fact two questions:
- how to correctly implement the connect method (called by JAVA) ?
- how to get & pass a reference of type 'type_of_P' ? (I got error when CProxy_type_of_P proxy(m->ckid))

Does it make sense?

Christian

On 05/25/2010 05:20 PM, Kale, Laxmikant V wrote:

Why not use the sync method solution? (and I assume you declared m1 to be threaded).

 

(And to understand your problem, a little more detail will be useful. Who created the callback? (m1 or m2)? Etc. Showing code fragment omitting all but the relevant calls will be good.)

 

With sync method, it’d look like this

 

M1() { ……; proxy.m2();  … }

M2(){… }

 

In .ci: m1 is threaded and m2 is sync.

 

--

Laxmikant Kale                  http://charm.cs.uiuc.edu

Professor, Computer Science     kale AT illinois.edu

201 N. Goodwin Avenue           Ph:  (217) 244-0094

Urbana, IL  61801-2302          FAX: (217) 265-6582

 

 

From: charm-bounces AT cs.uiuc.edu [mailto:charm-bounces AT cs.uiuc.edu] On Behalf Of Christian Perez
Sent: Tuesday, May 25, 2010 10:00 AM
To: Filippo Gioachin
Cc: charm AT cs.uiuc.edu
Subject: Re: [charm] how to suspend/resume a chare ?

 

Hello,

CkCallbackResumeThread() seems to be the perfect answer for one process ... but it fails when using several processes :
<<
Fatal error on PE 1> Called thread_delay on different processor than where callback was created
>>

Is there a standard mechanism to solve this issue or should I use an ad-hoc solution by forcing the
creation of a local chare?

My strong constraint is that m1 can not be spitted in two :(

Christian

On 05/24/2010 11:01 PM, Filippo Gioachin wrote:

Christian,

 

for your purposes, I would suggest looking at the manual on section 3.2.1 (Entry Method Attributes) regarding "threaded" and "sync" entry methods. A combination of the two (m1 threaded and m2 sync) should solve your problem.

Additionally, callbacks are very useful to resume threads as well; 3.15.2 shows how CkCallbackResumeThread can be used to resume m1().

Please remember that other entry methods may run while m1 is suspended, including other m1 methods.

 

Filippo

 

On Thu, May 20, 2010 at 03:58, Christian Perez <christian.perez AT inria.fr> wrote:

Hello,

I'd like to know how to block a thread. Here is a simple version of what
I'd like to do:

Chare A:
  m1() {
    do some computation
    invoke method m2 on chare B
    wait for the completion of method m2
    do something else
  }

I've tried to use some callback mechanism but the problem is that
I can not split m1 in two :(

So, is there a wait to suspend the execution (and also how to resume it) ?

Thank you!

Christian Perez

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--
Filippo Gioachin
PhD Candidate
Department of Computer Science
University of Illinois at Urbana-Champaign
Ph: +1-217-333-4764