On Jun 5, 2013, at 10:52 PM, Haggai Eran <hagg...@mellanox.com> wrote:

>> Haggai: A verb to resize a registration would probably be a helpful
>> step. MPI could maintain one registration that covers the sbrk
>> region and one registration that covers the heap, much easier than
>> searching tables and things.
> 
> That's a nice idea. Even without this verb, I think it is possible to
> develop a registration cache that covers those regions though. When you
> find out you have some part of your region not registered, you can
> register a new, larger region that covers everything you need. For new
> operations you only use the newer region. Once the previous, smaller
> region is not used, you de-register it.


I'm not sure what you mean.  Are you saying I should do something like this:

MPI_Init() {
// the first MPI function invoked
  mpi_sbrk_save = sbrk();
  ibv_reg_mr(..., 0, mpi_sbrk_save, ...);
  ...
}

MPI_Send(buffer, ...) {
  if (mpi_sbrk_save != sbrk())
      mpi_sbrk_save = sbrk();
      ibv_rereg_mr(..., 0, mpi_sbrk_save, ...);
  ...
}

I don't think this covers other memory regions, like those added via mmap, 
right?

-- 
Jeff Squyres
jsquy...@cisco.com
For corporate legal information go to: 
http://www.cisco.com/web/about/doing_business/legal/cri/

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