SHMEM: there is a wait_until call that the responder calls that basically waits until the value in the memory location changes. Then there is shmem_barrier_all, in which the responder could also have participated.
MPI: In passive mode operation - the requestor (origin) needs to unlock a window (or flush), and send a message to the responder (target) that allows the target to inspect the data. There is some talk in MPI Forum to introduce a call that does MPI_Put with notify, but it doesn’t exist currently. If it was introduced, maybe it could use the feature you’re suggesting? Thanks, Sayantan. On 10/21/15, 9:51 AM, "Paul Grun" <[email protected]> wrote: >What are those mechanisms that MPI and SHMEM use? > >Wouldn't it be useful if the requester could simply use REMOTE_CQ_DATA and be >assured that the responder wouldn't get the completion until the data had been >placed into cache? >-Paul > >-----Original Message----- >From: Sur, Sayantan [mailto:[email protected]] >Sent: Wednesday, October 21, 2015 9:50 AM >To: Paul Grun; [email protected] >Subject: Re: [ofiwg] A question on FI_DELIVERY_COMPLETE > >Having the notification at the requester is useful for MPI RMA or SHMEM use >cases. This allows MPI/SHMEM to wait for a local event that indicates remote >completion. The responder side is passive in these use cases. > >Both MPI and SHMEM have different mechanisms to let the responder know when it >is able to look at the data. > >Thanks, >Sayantan. > >From: ><[email protected]<mailto:[email protected]>> > on behalf of Paul Grun <[email protected]<mailto:[email protected]>> >Date: Wednesday, October 21, 2015 at 9:33 AM >To: "[email protected]<mailto:[email protected]>" ><[email protected]<mailto:[email protected]>> >Subject: [ofiwg] A question on FI_DELIVERY_COMPLETE > >Here’s my understanding of how FI_DELIVERY_COMPLETE works on the *responder* >end: If you are doing an RMA operation, and the requester uses CQ_REMOTE_DATA >to signal the end of the transfer to the responder, and the responder has >FI_DELIVERY_COMPLETE set, then the responder won’t get a completion event >until the data is actually visible to the responder. > >I ask because the man pages imply that FI_DELIVERY_COMPLETE, which is an >operation flag, applies only to the requester side. But it is much less >important to notify the requester that data is visible to the responder, than >it is to notify the responder itself. > >Comments? >-Paul > > >Cray Inc. >Office: (503) 620-8757 >Mobile: (503) 703-5382 > _______________________________________________ ofiwg mailing list [email protected] http://lists.openfabrics.org/mailman/listinfo/ofiwg
