osc/sm: fix pscw synchronization #925
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The osc/sm component was using a simple counter to determine if all expected posts had arrived to start a PSCW access epoch. This is incorrect as a post may arrive from a peer that isn't part of the current start group. There are many ways this could have been fixed. This commit adds an n^2 bitmap. When a process posts it sets a bit in the bitmap associated with the access rank to indicate the post is complete. The access rank checks for and clears the bits associated with all the processes in the start group. The bitmap requires comm_size ^ 2 bits of space. This should be managable as most nodes have relatively small numbers of processes. If this changes another algorigthm can be implemented. Signed-off-by: Nathan Hjelm <hjelmn@lanl.gov>
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Thanks to Steffen Christgau for catching this. I never tested the PSCW synchronization in osc/sm. The MTT tests all use the antiquated MPI_Win_create and not MPI_Win_allocate so they never cover the osc/sm path. |
Signed-off-by: Nathan Hjelm <hjelmn@lanl.gov>
Signed-off-by: Nathan Hjelm <hjelmn@lanl.gov>
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Added commits to fix selection and fix osc/pt2pt pscw on 0 size groups. |
hjelmn
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Sep 23, 2015
osc/sm: fix pscw synchronization
jsquyres
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Sep 19, 2016
…-hcoll-coll_request-v1.10 BufFix for coll/hcoll: coll_request must be set to ACTIVE when alloced
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The osc/sm component was using a simple counter to determine if all
expected posts had arrived to start a PSCW access epoch. This is
incorrect as a post may arrive from a peer that isn't part of the
current start group. There are many ways this could have been fixed.
This commit adds an n^2 bitmap. When a process posts it sets a bit in
the bitmap associated with the access rank to indicate the post is
complete. The access rank checks for and clears the bits associated
with all the processes in the start group.
The bitmap requires comm_size ^ 2 bits of space. This should be
managable as most nodes have relatively small numbers of processes. If
this changes another algorigthm can be implemented.
Signed-off-by: Nathan Hjelm hjelmn@lanl.gov