Dear Kathryn and all, I try to answer to the concerns mentioned at the telecon on April 18, 2013 an in your notes about this telecon: ( https://svn.mpi-forum.org/trac/mpi-forum-web/wiki/MPI3Tools/notes-2013-04-18 )
- Concerns raised: - This complicated scheme means that implementors and tool developers need to become Fortran experts. We would need a standardized wrapper generator to help with complexity.
In principle, whether there are only two linker names, e.g., - MPI_Isend (for the C MPI routine), and - mpi_isend__ (for the Fortran MPI routine, mapped from Fortran MPI_ISEND to this linker name through the mpi module and in mpif.h together with the Fortran compiler's compiler-dependent linker name mangling), or whether there are some more linker names with marginal changes in the argument list, e.g., - mpi_isend__ uses INTEGER handles - mpi_isend_f08__ uses these TYPE(MPI_Comm) handles, etc. should not be a great deal. With the new MPI-3.0, a profiling provider must mainly compile the same set of profiling wrappers several times with small modifications. These modifications are full systematic and apply to: - Which linker name must be used. - How handle arguments are done (this is only a theoretical aspect because old-style INTEGER handles and new-style TYPE(MPI_Comm) ... handles are internally the same: INTEGER. - How the buffer arguments are passed: this is the only real new stuff. - Whether the ierror argument is optional or not. - How Fortran callback procedures are passed (this is also as in MPI-2) Therefore it looks complicated, but it is not. I do not plan to write and additional advice to users for the user that are tools provider. I hope this email is enough to resolve this concern.
- What if application developers choose to call the various linker names directly instead of the high level MPI call?
I'll add an advice to users at page 6 line 40 in binding-2_Sec.17.1.5_2013-04-18.pdf (see previous email): Advice to users. The additional C routines MPI_..._cdesc, MPI_..._f08cb, and MPI_..._fcb for the implementation schemes B2 an B3 should not be called by application program, i.e., an application program that uses these {\em internal} routines does not conform to this \MPI/ standard. These routine names and their interfaces are standardized only for profiling purpose, i.e., that the routines can be intercepted with a profiling wrapper that internally calls the corresponding PMPI_..._cdesc, PMPI_..._f08cb, and PMPI_..._fcb routines. These additional MPI_... and PMPI_... C routines are not or only partially available if B2 and B3 is not or only partially used in the implementation of an \MPI/ library. This is described with the macros as follows. End of advice to users. I hope that this is clear enough, and that this advice resolves the second concern. Best regards Rolf ----- Original Message -----
From: "Kathryn Mohror" <[email protected]> To: [email protected] Sent: Thursday, April 18, 2013 10:31:07 PM Subject: Re: [Mpi3-tools] Next telecon tomorrow 4/18 Hi Rolf,
Thanks for the corrections and additions. I updated the wiki accordingly.
Kathryn
On Apr 18, 2013, at 12:31 PM, Rolf Rabenseifner < [email protected]
wrote:
Dear kathryn,
Good catch, here only a few small corrections and additions:
1) Now, in Fortran if you declare the buffer in a particular way, the compiler produces a descriptor instead of using a pointer, where a descriptor is a pointer plus some description of the buffer. --> Now, in Fortran if the MPI library (in the mpi_f08 or mpi module or mpif.h) declares the buffer ....
2) different linker names for routines in MPI applications. --> different linker names for the same MPI operation. The appropriate mapping of the MPI call is done through the specifications within the mpi_f08 or mpi module or mpif.h
3) After "Some routines will be able to be intercepted ...": - Special macros in mpi.h report to the tools, which linker names are provided and whether interception through the C interface is available. Based on these macros, all needed tool wrappers can be generated.
Best regards Rolf
----- Original Message -----
From: "Kathryn Mohror" < [email protected] > To: [email protected] Sent: Thursday, April 18, 2013 9:14:06 PM Subject: Re: [Mpi3-tools] Next telecon tomorrow 4/18 Hi all,
For anyone who missed the call, I put some notes on the wiki. Hopefully, I got the Fortran details right. Anyone with more expertise in Fortran than I have is welcome to correct me!
Kathryn
On Apr 17, 2013, at 10:13 AM, Kathryn Mohror < [email protected] > wrote:
Hi all,
This is a reminder of our next telecon tomorrow 4/18 at 8:00 AM PDT, 11:00 AM EDT. The Webex information is posted on the wiki: https://svn.mpi-forum.org/trac/mpi-forum-web/wiki/MPI3Tools
I expect the main topic of discussion will be the issues dealing with the new Fortran interface in MPI-3 as they relate to tools. Rolf and Craig will join the call to fill us in on the details.
If there is time, other topics may include: - MPI_Pcontrol Fortran problem - Updates to the MQS document - Possible change in telecon time to accommodate changed schedules - What is the openMP tools WG doing for DLL loading? - Status of ticket #357, threading problems in MPI-3
Kathryn
______________________________________________________________ Kathryn Mohror, [email protected] , http://people.llnl.gov/mohror1 CASC @ Lawrence Livermore National Laboratory, Livermore, CA, USA
_______________________________________________ Mpi3-tools mailing list [email protected] http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi3-tools
______________________________________________________________ Kathryn Mohror, [email protected] , http://people.llnl.gov/mohror1 CASC @ Lawrence Livermore National Laboratory, Livermore, CA, USA
_______________________________________________ Mpi3-tools mailing list [email protected] http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi3-tools
-- Dr. Rolf Rabenseifner . . . . . . . . . .. email [email protected] High Performance Computing Center (HLRS) . phone ++49(0)711/685-65530 University of Stuttgart . . . . . . . . .. fax ++49(0)711 / 685-65832 Head of Dpmt Parallel Computing . . . www.hlrs.de/people/rabenseifner Nobelstr. 19, D-70550 Stuttgart, Germany . . . . (Office: Room 1.307) _______________________________________________ Mpi3-tools mailing list [email protected] http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi3-tools
______________________________________________________________ Kathryn Mohror, [email protected] , http://people.llnl.gov/mohror1 CASC @ Lawrence Livermore National Laboratory, Livermore, CA, USA
_______________________________________________ Mpi3-tools mailing list [email protected] http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi3-tools
-- Dr. Rolf Rabenseifner . . . . . . . . . .. email [email protected] High Performance Computing Center (HLRS) . phone ++49(0)711/685-65530 University of Stuttgart . . . . . . . . .. fax ++49(0)711 / 685-65832 Head of Dpmt Parallel Computing . . . www.hlrs.de/people/rabenseifner Nobelstr. 19, D-70550 Stuttgart, Germany . . . . (Office: Room 1.307)