Re: [OMPI devel] RFC: convert send to ssend

On Aug 24, 2009, at 9:24 PM, Patrick Geoffray wrote: Ralph Castain wrote: Not quite that simple, Patrick. Think of things like MPI_Sendrecv, where the "send" call is below that of the user's code. You have a point, Ralph. Although, that would be 8 more lines to add to the user MPI code

Re: [OMPI devel] RFC: convert send to ssend

Ralph Castain wrote: Not quite that simple, Patrick. Think of things like MPI_Sendrecv, where the "send" call is below that of the user's code. You have a point, Ralph. Although, that would be 8 more lines to add to the user MPI code to define a MPI_Sendrecv macro :-) Seriously, this

Re: [OMPI devel] RFC: convert send to ssend

On Aug 24, 2009, at 5:33 PM, Patrick Geoffray wrote: George Bosilca wrote: I know the approach "because we can". We develop an MPI library, and we should keep it that way. Our main focus should not diverge to provide I would join George in the minority on this one. "Because we can" is

Re: [OMPI devel] RFC: convert send to ssend

George Bosilca wrote: I know the approach "because we can". We develop an MPI library, and we should keep it that way. Our main focus should not diverge to provide I would join George in the minority on this one. "Because we can" is a slippery slope, there is value in keeping things simple,

Re: [OMPI devel] RFC: convert send to ssend

On Aug 24, 2009, at 1:35 PM, Ashley Pittman wrote: > The point of b is for sysadmins (or individual developers) who want to > force there to *always* be correct MPI applications. But couldn't the sysadmin equally well write a config file to achieve the same effect should they want to?

Re: [OMPI devel] RFC: convert send to ssend

We spent more time over emails on this thread than the time required to write the patch. As apparently I'm the only one concerned about what we have in our code base or the only one that do not perceive the usefulness of such a feature, I belong to an ignorable minority. As long as you

Re: [OMPI devel] RFC: convert send to ssend

On Aug 24, 2009, at 2:26 PM, George Bosilca wrote: > My point is that this is a fairly trivial-to-implement feature. It > can even be done in a way that doesn't impact performance at all > (default to compile out). It is more trivial than this: mpirun -np 2 --mca btl_tcp_rndv_eager_limit 0

Re: [OMPI devel] RFC: convert send to ssend

On Aug 24, 2009, at 13:25 , Jeff Squyres wrote: On Aug 24, 2009, at 11:35 AM, George Bosilca wrote: As a side note, a very similar effect can be obtained by decreasing the eager size of the BTLs to be equal to the size of the match header, which is about 24 bytes. I disagree with this

Re: [OMPI devel] RFC: convert send to ssend

Hi Ashley, My understanding is that this behavior would not be enabled by default in the standard debug build. The "always convert to synchronous sends" mode would be an additional configure-time option. Samuel K. Gutierrez Ashley Pittman wrote: On Mon, 2009-08-24 at 13:27 -0400, Jeff

Re: [OMPI devel] RFC: convert send to ssend

On Mon, 2009-08-24 at 13:27 -0400, Jeff Squyres wrote: > It's the difference between: > > a. if (0) { ... convert ... } Modern compilers will remove this code > as part of dead-code removal. > b. if (1) { ... convert ... } Modern compilers will remove the "if > (1)" and always execute the

Re: [OMPI devel] RFC: convert send to ssend

On Aug 24, 2009, at 12:14 PM, Ashley Pittman wrote: > - compiled out > - compiled in, always convert standard send to sync send > - compiled in, use MCA parameter to determine whether to convert > standard -> sync > > And we can leave the default as "compiled out". > > Howzat? I don't

Re: [OMPI devel] RFC: convert send to ssend

On Aug 24, 2009, at 11:35 AM, George Bosilca wrote: As a side note, a very similar effect can be obtained by decreasing the eager size of the BTLs to be equal to the size of the match header, which is about 24 bytes. I disagree with this statement. ;-) We currently don't export the BTL or

Re: [OMPI devel] RFC: convert send to ssend

On Mon, 2009-08-24 at 10:52 -0400, Jeff Squyres wrote: > Adapting that to this RFC, perhaps something like this: > > - compiled out > - compiled in, always convert standard send to sync send > - compiled in, use MCA parameter to determine whether to convert > standard -> sync > > And we can

Re: [OMPI devel] RFC: convert send to ssend

For the record, I see an big interest in this. Sometimes, you have to answer calls for tender featuring applications that must work with no code change, even if the code is completely not MPI-compliant. That's sad, but true (no pun intended :-)) Sylvain On Mon, 24 Aug 2009, George Bosilca

Re: [OMPI devel] RFC: convert send to ssend

Do people know that there exist tools for checking MPI code correctness? Many, many tools and most of them are freely available. Personally I don't see any interest of doing this, absolutely no interest. There is basically no added value to our MPI, except for a very limited number of

Re: [OMPI devel] RFC: convert send to ssend

Hi Jeff, Sounds good to me. Samuel K. Gutierrez Jeff Squyres wrote: The debug builds already have quite a bit of performance overhead. It might be desirable to change this RFC to have a similar tri-state as the MPI parameter checking: - compiled out - compiled in, always check - compiled

Re: [OMPI devel] RFC: convert send to ssend

Hi all, How about exposing this functionality as a run-time parameter that is only available in debug builds? This will make debugging easier and won't impact the performance of optimized builds. Just an idea... Samuel K. Gutierrez > > - "Jeff Squyres" wrote: > >>

Re: [OMPI devel] RFC: convert send to ssend

- "Jeff Squyres" wrote: > Does anyone have any suggestions? Or are we stuck > with compile-time checking? I didn't see this until now, but I'd be happy with just a compile time option so we could produce an install just for debugging purposes and have our users

Re: [OMPI devel] RFC: convert send to ssend

Given the limited scope, would it make sense to somehow add this to the trace library (or a separate debug lib) - i.e., can we do it via a lib that inserts itself between the MPI binding and PMPI call? I would hate to duplicate the code in something like sendrecv, but I wonder if we could refactor

[OMPI devel] RFC: convert send to ssend

WHAT: MCA parameter for converting all standard mode MPI sends to synchronous mode sends WHY: helpful in debugging user apps WHERE: here's the output from "svn st" M ompi/runtime/params.h M ompi/runtime/ompi_mpi_params.c M ompi/mpi/c/send.c M ompi/mpi/c/send_init.c M