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Subject: Re: [OMPI devel] sm BTL "extra procs"
From: Eugene Loh (Eugene.Loh_at_[hidden])
Date: 2008-12-23 13:06:28


Well, and we only allocate extra FIFOs, but we don't initialize them.
Also, the eager free list is initially set up to grow with the number of
connections (some attempt to avoid deadlock, I imagine), but this
initial eager free list size doesn't account for the extra procs either.

So, shall we remove that code and associated MCA parameters? Or, as
Lenny suggests, just back the default down to 0 and leave the code in?

Richard Graham wrote:

>Not needed now. Since we did not want to deal with trying to grow the
>shared memory file after it's allocation, with all the required
>synchronization, we allocated extra memory up front - for dynamic process
>control. Since this has never been enabled, we really don't need this extra
>memory.
>
>On 12/22/08 11:47 AM, "Eugene Loh" <Eugene.Loh_at_[hidden]> wrote:
>
>
>>Why does the sm BTL allocate "extra procs"?
>>
>>E.g.,
>>
>>https://svn.open-mpi.org/trac/ompi/browser/branches/v1.3/ompi/mca/btl/sm/btl_s
>>m.c?version=19785#L403
>>
>>In particular:
>>
>>*) sm_max_procs is -1 (so there is no max)
>>*) sm_sm_extra_procs (sic, this is the ompi_info name) is 2
>>
>>So, if there are n procs on the node, it allocates FIFOs for n*(n+2)
>>connections. Why?
>>
>>