Charm++ parallel programming system

[Evghenii Gaburov <e-gaburov AT northwestern.edu>]

Hi,

> We shave many more examples of structured dagger now, and we will add them
> to the documentation soon; but you could start exploring them with the
> manual and any example program from the cha++ distribution. If you are
> interested, I will send you a chapter about it.
Yes, please, I would love to have a look at this chapter. Perhaps this will 
explain how can I implement it in my code.

Thanks!

Cheers,
 Evghenii

> 
> What AMPI can do, that  dagger cannot, is to be able to block for remote
> data deep inside a function call sequence (f calls g calls h, which then
> blocks for a receive). With dagger, you bring up all remote dependencies
> at the top level, in the run method in the .ci file. This is a matter of
> style, and some prefer one over the other. But it gives a good separation
> of concerns, which we find especially useful when working in a
> collaborative application. The application scientist can focus on the
> sequential code, once the parallel structure and remote dependences are
> agreed upon, and encoded in the structured dagger notation.
> 
> 
> -- 
> 
> Laxmikant (Sanjay) Kale         http://charm.cs.uiuc.edu
> <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
> 
> 
> 
> 
> 
> 
> On 11/8/11 1:23 PM, "Evghenii Gaburov" 
> <e-gaburov AT northwestern.edu>
>  wrote:
> 
>> Hi,
>> 
>> Thanks for prompt replies.
>> 
>> I guess my question is if I were to start a project is there advantage of
>> me to use Charm over AMPI. One thing with AMPI, is that is can have  a
>> nice program flow like a normal MPI codes, with barriers and All_reduce ,
>> e.g.
>> 
>> Š do-work1 ..
>> MPI_Barrier(..)
>> .. do-work2 Š
>> MPI_Exchange() 
>> .. do-work3
>> MPI_Allreduce Š
>> finish-work
>> 
>> in one subroutine.
>> 
>> With Charm, as I have understood, it requires several method to be called
>> at each Barrier, exchange, reduction (via contribute, for example),  and
>> cannot be done in single routine. This kind of breaks the program flow,
>> e.g.
>> 
>> do_work1
>> { Š
>> contribute(do_work2) // MPI_Barrier(..)
>> }
>> do_work2()
>> {
>>  Š
>> proxy.do_work3(data);
>> }
>> do_work3(..)
>> {
>> Š
>> contribute(finish_work, CkReduction::sum_double);
>> }
>> finish_work(..)
>> {
>> ...
>> }
>> 
>> and this makes things a bit more difficult.
>> 
>> Also, does AMPI has C++ interface, particularly for PUP? So that I can do
>> same as in charm p|data, instead of pup_double(..) C routine?
>> 
>> Thanks,
>> Evghenii
>> 
>> On Nov 8, 2011, at 11:11 AM, Gengbin Zheng wrote:
>> 
>>> Hi,
>>> 
>>> AMPI is an implementation of MPI standard 1.1 on top of Charm++. The
>>> benefits you mentioned below from charm++ are retained in AMPI. Please
>>> refer to AMPI manual for the MPI extensions for doing load balancing
>>> and checkpointing.
>>> 
>>> It sometimes take some efforts to convert an MPI program to AMPI due
>>> to the multi-threading execution and global variable sharing. However,
>>> AMPI provides a set of tools to automate such process (please refer to
>>> recent AMPI papers for the information about the tools).
>>> 
>>> Having said that, since AMPI is a library implemented on top of
>>> charm++ (which means another layer, and associated overhead), it is
>>> mainly for legacy MPI application to take advantage of charm++
>>> benefits.
>>> 
>>> Gengbin
>>> 
>>> On Tue, Nov 8, 2011 at 10:50 AM, Evghenii Gaburov
>>> <e-gaburov AT northwestern.edu>
>>>  wrote:
>>>> Hi All,
>>>> 
>>>> I have been wondering, what is the advantage of CHARM vs AMPI, can I
>>>> achieve same level of functionality with AMPI as with CHARM?
>>>> 
>>>> I already use Charm for my projects, but I was wondering whether
>>>> charm's functionality such as automatic load-ballancing, migration,
>>>> checkpoints is also available in AMPI, and whether it is as easy to add
>>>> it to standard MPI program that will use AMPI backend?
>>>> 
>>>> Thanks!
>>>> 
>>>> Cheers,
>>>> Evghenii
>>>> 
>>>> --
>>>> Evghenii Gaburov, 
>>>> e-gaburov AT northwestern.edu
>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
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>> 
>> --
>> Evghenii Gaburov, 
>> e-gaburov AT northwestern.edu
>> 
>> 
>> 
>> 
>> 
>> 
>> 
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> 

--
Evghenii Gaburov, 
e-gaburov AT northwestern.edu