Library: collectives 2.0
Originally reported on Google Code with ID 42 ``` This is to log the UPC collectives 2.0 extensions.
For reference, the UPC Collectives 2.0 proposal can be found here: http://upc.lbl.gov/publications/UPC-Collectives-PGAS11.pdf
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Reported by `yzheng@lbl.gov` on 2012-05-22 23:45:21
Comments (7)
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Account Deleted ``` To pick up just one issue from the many valid questions raised. We discussed the issue of handles and so on. I would have liked to use upc_fence to guarantee completion of a non-blocking collective. Problem is, this requires changes in the "existing" compiler, rather than just adding a library. We considered that a no-go at the time.
OTOH if there are other examples where handles are used by other libraries, maybe we can put a *little bit* of pressure on the language specification to accept handles and guarantee completion based on upc_fence?
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Reported by `ga10502` on 2012-06-15 14:50:58
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Account Deleted ``` Having upc_fence guarantee completion of a non-blocking operation is already part of the Cray proposal for non-blocking memcpy functions. Yes, it may require changes to existing fence implementations, but that is necessary for the fence to remain a true fence in the presence of these new non-blocking alternatives. ```
Reported by `johnson.troy.a` on 2012-06-15 14:59:00
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Account Deleted ``` I have "conceded" the fence-syncs-nb-memcpy argument in my latest counter-proposal offered in issue #41, but have preserve the explicit handles and the requirement to "sync" them. I think if we can come to an agreement on that proposal (which seems closer to resolution than Collectives-2.0), then we should attempt to do something as analogous as possible here. ```
Reported by `phhargrove@lbl.gov` on 2012-06-16 00:35:45
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Account Deleted Reported by `gary.funck` on 2012-07-03 18:07:50 - Labels added: Type-Lib-Required - Labels removed: Type-Enhancement
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Account Deleted Reported by `gary.funck` on 2012-07-03 18:09:31
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Account Deleted ``` All "brand new" library proposals are targeted for starting in the "Optional" library document. Promotion to the "Required" document comes later after at least 6 months residence in the ratified Optional document, and other conditions described in the Appendix A spec process. ```
Reported by `danbonachea` on 2012-08-17 17:53:59 - Labels added: Type-Lib-Opt - Labels removed: Type-Lib-Required
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``` Feedback from "users" to be resolved:
Some initial comments and questions regarding "Collectives 2.0":
Things that are good: --Teams --The greater variety of collectives --Support for asynchronous calls
On the other hand, it is very complicated, the function calls have too many parameters, and it isn't integrated well into the rest of UPC.
Some specific comments:
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Reported by `yzheng@lbl.gov` on 2012-06-14 18:04:43 - Labels added: Milestone-Spec-1.4