Simple strides are a fairly specific use case that apply to dense matrices and regular problems. I am not denying that those problems exist, but they are a subset. As I understand it, regular applications are a shrinking fraction of the application domain.
Does any current hardware support strides natively? If not, maybe we have a little time to work out that interface. From: Jeff Hammond [mailto:[email protected]] Sent: Thursday, October 29, 2015 3:09 PM To: Underwood, Keith D <[email protected]> Cc: Hefty, Sean <[email protected]>; Howard Pritchard <[email protected]>; [email protected] Subject: Re: [ofiwg] strided IOVs Both GA/ARMCI and SHMEM utilize regular aka simple strided operations in RMA. GA_Acc/ARMCI_AccS/MPI_Accumulate map to fi_atomic, that means those also need to support strided, assuming RMA does. I think only simple strided is worth supporting, because it is O(1) metadata. General gather/scatter ala iovec is unlikely to optimizable relative to a higher-level software implementation, so I don't see a good reason to put it into OFI. Jeff On Thu, Oct 29, 2015 at 4:46 AM, Underwood, Keith D <[email protected]<mailto:[email protected]>> wrote: Exactly. However, we should be careful about what we are adding here. A strided interface is a very specific special case that applies to regular problems. There is a bready of MPI derived datatype capabilities that are not covered by a simple stride. What are the objectives for covering datatypes? Is the IOVEC interface the right place to glue in the first handling of a special case of datatypes? > -----Original Message----- > From: > [email protected]<mailto:[email protected]> > [mailto:ofiwg-<mailto:ofiwg-> > [email protected]<mailto:[email protected]>] On > Behalf Of Hefty, Sean > Sent: Wednesday, October 28, 2015 3:14 PM > To: Hefty, Sean <[email protected]<mailto:[email protected]>>; Howard > Pritchard > <[email protected]<mailto:[email protected]>> > Cc: [email protected]<mailto:[email protected]> > Subject: Re: [ofiwg] strided IOVs > > > I need more context to understand how writing X bytes every N bytes > > into a one-time use receive buffer is useful. > > FWIW, someone sent me this link: > > http://people.csail.mit.edu/fred/ghost_cell.pdf > > as an example. > _______________________________________________ > ofiwg mailing list > [email protected]<mailto:[email protected]> > http://lists.openfabrics.org/mailman/listinfo/ofiwg _______________________________________________ ofiwg mailing list [email protected]<mailto:[email protected]> http://lists.openfabrics.org/mailman/listinfo/ofiwg -- Jeff Hammond [email protected]<mailto:[email protected]> http://jeffhammond.github.io/
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