[mpiwg-p2p] Next meeting: 14th April 2014 11am Central US

[Jeff Hammond]

I cannot attend. My trac acct is fixed though. Will upload material for discussion by others. 

Jeff

Sent from my iPhone

> On Apr 13, 2014, at 5:24 AM, Daniel Holmes <dholmes at epcc.ed.ac.uk> wrote:
> 
> Hi all,
> 
> The next point-to-point teleconference will be on Monday 14th April 2014 at 11am Central US via webex.
> 
> Connection details are on the p2p wiki.
> 
> Agenda:
> 1) Streams: I have some notes - see below - from a discussion last week with Bill Gropp, Torsten (et al from the EPiGRAM project)
> 2) Receive_reduce
> 3) Arecv
> 4) AOB (= any other business)
> 
> Cheers,
> Dan.
> 
> Streams
> =======
> QCDOC developers want persistent channel semantics; actually use one-sided, multi-value variables
> Breaking message boundaries enables pipe-lining - makes it fundamentally different to RMA?
> Libraries exist to do this - what are they?
> Streaming is well defined in OpenSPL
> Papers from the MPI-2 era (about RMA) suggest writing papers on this and getting feedback
> Reach out to other communities, e.g. SKA - Square Kilometre Array
> Should this be added to MPI or added as a library on top - does this need small enabling changes
> Bill suggests we craft a broad-visibility paper
> Affects the discussion on Arecv, which would be handled by streams?
> Getting MPI to manage/allocate memory (as in Arecv) is dangerous and bad
> 
> Flow-control
> ============
> May just be remote notification and a sequence of messages that remove the need for local notification - reduces protocol messages (from 3 to 1 per message)
> Integral part of streaming - turns global flow-control problem into local buffer management
> May address load-imbalance? Hmm
> 
> -- 
> Dan Holmes
> Applications Consultant in HPC Research
> EPCC, The University of Edinburgh
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> The Kings Buildings
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> T: +44(0)131 651 3465
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> 
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