Re: [boost] Multicore-BGL

Subject: Re: [boost] Multicore-BGL
From: Giorgio Zoppi (giorgio.zoppi_at_[hidden])
Date: 2010-05-30 15:34:55

2010/5/30 Jeremiah Willcock <jewillco_at_[hidden]>:
> On Sun, 30 May 2010, Giorgio Zoppi wrote:
>
>> 2010/5/30 Adam Merz <adammerz_at_[hidden]>:
>>>
>>> Giorgio Zoppi <giorgio.zoppi <at> gmail.com> writes:
>>>>
>>>> we're intersted in how to optimize BGL on Multicore for adding our
>>>> standard Bellman-Ford algorithms for optical networks.
>>>> How do the current boost work on Multicore? BGL is thread-safe? Which
>>>> parts are required to optimize?
>>>
>>> I believe what you're interested in is the Parallel BGL. See
>>>
>>> http://www.boost.org/doc/libs/release/libs/graph_parallel/doc/html/index.html
>>> and
>>> http://osl.iu.edu/research/pbgl/
>>
>> I skimmed the doc, however we're more fit in a multicore solution than
>> a distributed process solution. I cannot find something about that in
>> the doc. Any hints?
>
> We are in the process of adding shared-memory/hybrid parallelism to PBGL,
> but that's still in a very early stage.  You can run multiple MPI processes
> on the same machine (running them on different cores) and they will
> communicate using shared memory.  One issue that comes up is that memory is
> often the limitation for graph algorithms, not CPU performance; in that
> case, multicores don't really do much for performance.  Are you using more
> expensive algorithms that aren't memory intensive?  If so, there might be
> ways to do simple things with existing BGL algorithms to make them run with
> shared memory (for example, adding OpenMP pragmas).

So if the graph is with sparse matrix, you could provide a more
compact implementation
and modify (parallelize) your algorithms.

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