Open MPI logo

Open MPI Development Mailing List Archives

  |   Home   |   Support   |   FAQ   |   all Development mailing list

Subject: Re: [OMPI devel] RFC: eliminating "descriptor" argument from sendi function
From: Jeff Squyres (jsquyres_at_[hidden])
Date: 2009-02-23 11:04:24


On Feb 23, 2009, at 10:37 AM, Eugene Loh wrote:

> I sense an opening here and rush in for the kill...

:-)

> And, why does the PML pass a BTL argument into the sendi function?
> First, the BTL argument is not typically used. Second, if the BTL
> sendi function wants to know what BTL it is,... uh, doesn't it
> already know??? Doesn't a BTL know who it is? Why, then, should
> the PML have to tell it?

I suspect that it's passing in the BTL *module* argument, which may
have specific information about the connection that is to be used.

Example: if I have a dual-port IB HCA, Open MPI will make 2 different
openib BTL modules. In this case, the openib BTL will need to know
exactly which module the PML is trying to sendi on.

-- 
Jeff Squyres
Cisco Systems