[mpich-discuss] Affinity with MPICH_ASYNC_PROGRESS

[Jim Dinan]

On 2/23/13 8:21 PM, Jeff Hammond wrote:
> I think the only way for async progress to work well is to have
> fine-grain locking since of MPI, as is done in PAMID.  Any
> implementation that resorts to fat-locking is probably better off
> without async progress unless the application is doing something
> really silly (like never calling MPI on a rank that is the target of
> MPI RMA).

Jeff,

If processes are entering the MPI progress engine frequently enough that 
they are competing with the comm thread to get the (per-process, not 
per-node) library lock, the additional comm thread is probably not needed.

  ~Jim.