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From: Gleb Natapov (glebn_at_[hidden])
Date: 2007-08-29 09:48:07


Is this trunk or 1.2?

On Wed, Aug 29, 2007 at 09:40:30AM -0400, Terry D. Dontje wrote:
> I have a program that does a simple bucket brigade of sends and receives
> where rank 0 is the start and repeatedly sends to rank 1 until a certain
> amount of time has passed and then it sends and all done packet.
>
> Running this under np=2 always works. However, when I run with greater
> than 2 using only the SM btl the program usually hangs and one of the
> processes has a long stack that has a lot of the following 3 calls in it:
>
> [25] opal_progress(), line 187 in "opal_progress.c"
> [26] mca_btl_sm_component_progress(), line 397 in "btl_sm_component.c"
> [27] mca_bml_r2_progress(), line 110 in "bml_r2.c"
>
> When stepping through the ompi_fifo_write_to_head routine it looks like
> the fifo has overflowed.
>
> I am wondering if what is happening is rank 0 has sent a bunch of
> messages that have exhausted the
> resources such that one of the middle ranks which is in the process of
> sending cannot send and therefore
> never gets to the point of trying to receive the messages from rank 0?
>
> Is the above a possible scenario or are messages periodically bled off
> the SM BTL's fifos?
>
> Note, I have seen np=3 pass sometimes and I can get it to pass reliably
> if I raise the shared memory space used by the BTL. This is using the
> trunk.
>
>
> --td
>
>
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--
			Gleb.