Open MPI logo

Open MPI Development Mailing List Archives

  |   Home   |   Support   |   FAQ   |   all Development mailing list

Subject: Re: [OMPI devel] Affect of compression on modex and launch messages
From: Gleb Natapov (glebn_at_[hidden])
Date: 2008-04-07 09:15:34


On Mon, Apr 07, 2008 at 07:07:38AM -0600, Ralph H Castain wrote:
>
>
>
> On 4/7/08 7:04 AM, "Gleb Natapov" <glebn_at_[hidden]> wrote:
>
> > On Fri, Apr 04, 2008 at 10:52:38AM -0600, Ralph H Castain wrote:
> >> With compression "on", you will get output telling you the original size of
> >> the message and its compressed size so you can see what was done.
> >>
> > I see this output:
> > uncompressed allgather msg orig size 67521 compressed size 4162.
> >
> > What is "allgather msg"
>
> It is the modex message - it is "shared" across all the procs via an
> allgather procedure
>
If I'll divide allgather msg size by number of processes I should get a
modex size of one process. Is this correct? Also can you explain how
allgather is implemented in orte (sorry if you already explained this once
and I missed it).

--
			Gleb.