On Jun 9, 2008, at 11:50 AM, Jeff Squyres wrote:
Please search through the archives of this list; as Brian mentioned, this topic has come up several times before. It's fairly boring to keep repeating the same arguments; we have lots of *new* things to argue about these days. ;-)
Unfortunately, I'm unable to find any trace of such discussion on the mailing lists (I checked users and devel). If someone can pinpoint me to the discussion thread I'll gladly read it.
I completely agree that we should follow the standard to the greatest possible extend, but then at least we should have our test codes following the same guidelines. It doesn't means I volunteer for anything ...
george.
On Jun 9, 2008, at 10:44 AM, George Bosilca wrote:Rainer, The snippet from the MPICH2 is irrelevant to the current discussion. It only concern set empty status. A quick grep in the MPICH2 source code (find . -name "*.[ch]" -exec grep -Hn MPI_ERROR {} \;) shows that they ALWAYS set the MPI_ERROR field in the status if they detect something wrong. george. On Jun 9, 2008, at 4:17 AM, Rainer Keller wrote:Hi, that's one of the mysteries of the MPI-1 standard. Nevertheless, we should be std. conforming. Therefore, I included the comment and omitted the setting of .MPI_ERROR. MPIch2 does not for the same reasons. Therefore I would say the tests are wrong. With best regards, Rainer PS: e.g. from mpich2-1.0.7: include/mpiimpl.h:2112 /* Do not set MPI_ERROR (only set if ERR_IN_STATUS is returned */ #define MPIR_Status_set_empty(status_) \ { \ if ((status_) != MPI_STATUS_IGNORE) \ { \ (status_)->MPI_SOURCE = MPI_ANY_SOURCE; \ (status_)->MPI_TAG = MPI_ANY_TAG; \ (status_)->count = 0; \ (status_)->cancelled = FALSE; \ } \ } On Sonntag, 8. Juni 2008, George Bosilca wrote:Here is what the MPI standard state: "In general, message passing calls do not modify the value of theerror code field of status variables. This field may be updated onlyby the functions in Section 3.7.5 which return multiple statuses. The field is updated if and only if such function returns with an error code of MPI ERR IN STATUS. Rationale. The error field in status is not needed for calls that return only one status, such as MPI WAIT, since that would only duplicate the information returned by the function itself. The current design avoids the additional overhead of setting it, in such cases. The field is needed for calls that return multiple statuses, since each request may have had a different failure. (End of rationale.)" First, the sentence start with "In general" which is not a limiting statement, it absolutely doesn't state that the field doesn't have to be set. Second, the reason cited in the rationale is completely fake.We're talking about one store instruction, while the simple usage ofthe status will generate a cache miss. On the other side, a simple grep in the ompi-tests shows that hundreds of tests use this MPI_ERROR over the return value. If test writers (which are supposed to know the standard quite well), do such things, I wonder how can we expect that the users will never do it. george. On Jun 6, 2008, at 12:04 PM, Brian Barrett wrote:Since this is not the first or second time we've had the discussion in the group, perhaps a comment in the code would be a good idea :). Brian On Jun 6, 2008, at 9:58 AM, Jeff Squyres wrote:George -- This is not correct. Note the comment that says to see MPI-1.2 section 3.2.5 page 22 (I think it means MPI-1.1). It says: "In general, message passing calls do not modify the value of the error code field of status variables. This field may be updated onlyby the functions in Section 3.7.5 which return multiple statuses."So we should not be setting status.MPI_ERROR here; you should check the return value from MPI_WAIT to get the error code. On Jun 6, 2008, at 11:53 AM, bosi...@osl.iu.edu wrote:Author: bosilca Date: 2008-06-06 11:53:17 EDT (Fri, 06 Jun 2008) New Revision: 18607 URL: https://svn.open-mpi.org/trac/ompi/changeset/18607 Log: Update the MPI_ERROR field as well. Text files modified: trunk/ompi/request/req_wait.c | 1 + 1 files changed, 1 insertions(+), 0 deletions(-) Modified: trunk/ompi/request/req_wait.c = = = = = = = = = = = = == ================================================================--- trunk/ompi/request/req_wait.c (original) +++ trunk/ompi/request/req_wait.c 2008-06-06 11:53:17 EDT (Fri, 06 Jun 2008) @@ -50,6 +50,7 @@ /* See MPI-1.2, sec 3.2.5, p.22 */ status->MPI_TAG = req->req_status.MPI_TAG; status->MPI_SOURCE = req->req_status.MPI_SOURCE; + status->MPI_ERROR = req->req_status.MPI_ERROR; status->_count = req->req_status._count; status->_cancelled = req->req_status._cancelled; } _______________________________________________ svn-full mailing list svn-f...@open-mpi.org http://www.open-mpi.org/mailman/listinfo.cgi/svn-full-- Jeff Squyres Cisco Systems _______________________________________________ devel mailing list de...@open-mpi.org http://www.open-mpi.org/mailman/listinfo.cgi/devel-- Brian Barrett Open MPI developer http://www.open-mpi.org/ _______________________________________________ devel mailing list de...@open-mpi.org http://www.open-mpi.org/mailman/listinfo.cgi/devel-- ---------------------------------------------------------------- Dipl.-Inf. Rainer Keller http://www.hlrs.de/people/keller HLRS Tel: ++49 (0)711-685 6 5858 Nobelstrasse 19 Fax: ++49 (0)711-685 6 5832 70550 Stuttgart email: kel...@hlrs.de Germany AIM/Skype:rusraink_______________________________________________ devel mailing list de...@open-mpi.org http://www.open-mpi.org/mailman/listinfo.cgi/devel-- Jeff Squyres Cisco Systems _______________________________________________ devel mailing list de...@open-mpi.org http://www.open-mpi.org/mailman/listinfo.cgi/devel
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