Good feedback -- thanks! /me tosses this idea to /dev/null On Aug 2, 2011, at 1:01 PM, Martin Schulz wrote:
I tend to agree with Bill - sure, tools could use such information, but, as Bill said, in most cases it is not sufficient information for tools anyway and they need to track additional request information. Also, most tools already have some kind of request tracking (since this is needed for many use cases) and adding a field for the request type to such a tracking mechanism is easy.
Martin
On Aug 2, 2011, at 8:33 AM, William Gropp wrote:
There are already requests for I/O operations on files (just not collective nonblocking file I/O).
For a tool, this isn't detailed enough - given a request at random, even for point-to-point, whether it is a send or receive, and whether it is persistent or not, is important.
However, requests are also on the critical path for performance. I'm opposed to anything that adds yet more overhead; there are also alternatives for tools to use (though they require much more work on the part of the tool developer).
Bill
On Aug 1, 2011, at 6:50 PM, Jeff Squyres wrote:
MPI now has 3 different types of requests that I can think of, with pending proposals for (at least) 2 more:
- point-to-point - collective - generalized - timers (proposed) - file (proposed)
Would it be worthwhile to have a simple introspection routine that can return an enum telling you the type of a request handle? E.g., MPI_REQUEST_GET_TYPE that has an OUT parameter that will be set to MPI_REQUEST_PT2PT, MPI_REQUEST_COLLECTIVE, MPI_REQUEST_GENERALIZED, etc.
I can generally see how this might be useful to applications, but I can't think of a "must have" kind of use case.
Does anyone else think that this would be valuable / useful?
-- Jeff Squyres [email protected] For corporate legal information go to: http://www.cisco.com/web/about/doing_business/legal/cri/
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William Gropp Director, Parallel Computing Institute Deputy Director for Research Institute for Advanced Computing Applications and Technologies Paul and Cynthia Saylor Professor of Computer Science University of Illinois Urbana-Champaign
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________________________________________________________________________ Martin Schulz, [email protected], http://people.llnl.gov/schulzm CASC @ Lawrence Livermore National Laboratory, Livermore, USA
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