[mpich-discuss] Affinity with MPICH_ASYNC_PROGRESS

[Jim Dinan]

On 2/25/13 9:30 AM, Jeff Hammond wrote:
>> It depends on the op.  We start processing the op as soon as the packet
>> header arrives.  For ops that send data to the target, if the data (payload
>> and datatype) has not all arrived at the time we enter the progress engine,
>> the op will be enqueued to finish later using an internal/device-level
>> request.  Ops that send a response to the origin process, always enqueue a
>> request that completes when we finish sending the response message.  Some
>> ops (notably, CAS and FOP and also Acc in some cases) embed the data payload
>> in the packet header, allowing us to handle them completely with a single
>> iteration through the progress engine.
>
> Is it possible to add an option to force the progress engine to finish
> RMA ops once they start?  That might help NWChem since it does larger
> transfers, particularly Acc.  Could this be an MPICH-specific info key
> on the window?

I'm not sure if that mode of operation would be compatible with the 
basic CH3 architecture.  We handle the data that has been received and 
then re-enter the progress engine, presumably because we could also 
receive data from other processes.  I'm not sure that we have the option 
to block on communication with a particular process at that level.

  ~Jim.