[mpi3-coll] Non-blocking Collectives Proposal Draft

Supalov, Alexander alexander.supalov at intel.com
Wed Oct 15 09:46:43 CDT 2008

Dear Torsten,

Thanks for the proposal. A couple of comments in the more old-fashioned

Generally, some sentences start with lower case letters that should be

Page 3, top. We probably should not explain here how to ensure progress
for nonblocking ops. This matter should be covered by the general
progress description elsewhere.

Page 3, lower half. Look how progress is defined in this list by
referring to the pt2pt progress rules.

Ibid. There are already 3 classes of requests: pt2pt, generalized, and
file I/O ones.

Page 3, bottom. How many nonblocking ops can overlap with a blocking
one? I.e., can one have the following situation:

Process 0			Process 1

MPI_Ibarrier(req)		MPI_Ibarrier(req)
MPI Bcast			MPI_Bcast

Page 5, bottom. 32767 simultaneous ops to support is a tall order. I'd
say, 1 (one) would be a good lower limit, thus allowing no overlap. Or
even 0 (zero), meaning no nonblocking collective support at all. The
rest of this passage would probably be better reformulated as an advice
to implementors.

In the margin: editing a PDF requires creativity (exemplified by the
earlier comments) or a pretty expensive Acrobat. Maybe we can find some
other way of distributing and commenting on our drafts?

Best regards.


-----Original Message-----
From: mpi3-coll-bounces at lists.mpi-forum.org
[mailto:mpi3-coll-bounces at lists.mpi-forum.org] On Behalf Of Torsten
Sent: Tuesday, October 14, 2008 9:47 PM
To: mpi3-coll at lists.mpi-forum.org
Subject: [mpi3-coll] Non-blocking Collectives Proposal Draft

Hello Working Group,
I finished a first draft of our non-blocking collectives proposal.
Please read it carefully and send comments to me or the list (e.g.,
marked-up pdf documents).

The draft is attached to this mail.

All the Best,

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