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Feature #315

Reduction Starting messages - Performance optimal solution

Added by Nikhil Jain over 5 years ago. Updated almost 2 years ago.

Status:
New
Priority:
Normal
Assignee:
Category:
SMP
Target version:
-
Start date:
02/06/2013
Due date:
02/28/2013
% Done:

70%


Description

Due to migratability, the current Chare Array reduction mechanic triggers partition wide broadcasts. This is problematic for several reasons.

1. For arrays which do not migrate, this is pure overhead.
2. For arrays which do not span the entire partition and will not migrate off their subset of cores, the message traffic to unused cores is overhead
3. This happens even when arrays are constructed with flags that disable anytime migrate and anytime insertion.

The task is to implement a version of the chare array reduction which can perform better for the very common case of no anytime migration and no anytime insertion. Notionally, the empty core and how many elements per core tracking issues should be something which can be determined after doneInserting completes. Possible extensions would be to allow for reset of such quantities in dynamic situations by doneInserting, or some other mechanism.


Related issues

Copied from Charm++ - Feature #29: Reduction Starting messages Closed 02/06/2013 02/28/2013

History

#1 Updated by Nikhil Jain over 5 years ago

  • Target version changed from 6.6.0 to 6.7.0

#2 Updated by Nikhil Jain over 5 years ago

Branched off as a separate issue to evaluate if a performance optimal solution has been added.

#3 Updated by Nikhil Jain over 3 years ago

  • Target version changed from 6.7.0 to 6.8.0

#4 Updated by Sam White over 2 years ago

  • Priority changed from High to Normal
  • Status changed from In Progress to New
  • Assignee changed from Harshitha Menon to Eric Mikida
  • Category set to SMP

Reassigning to Eric since he is already assigned the related issue.

#5 Updated by Eric Mikida over 2 years ago

  • Target version changed from 6.8.0 to 6.9.0

#6 Updated by Eric Mikida almost 2 years ago

  • Target version deleted (6.9.0)

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