Ticket 6637

Summary: The collective type selection logic in the PMIx plugin
Product: Slurm Reporter: Boris Karasev <karasev.b>
Component: PMIxAssignee: Tim Wickberg <tim>
Status: RESOLVED FIXED QA Contact:
Severity: C - Contributions    
Priority: --- CC: artpol84, karasev.b
Version: 19.05.x   
Hardware: Linux   
OS: Linux   
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Version Fixed: 19.05.0rc1 Target Release: ---
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Attachments: 0001-mpi-pmix-select-the-Tree-based-collective-type-for-e.patch

Description Boris Karasev 2019-03-04 22:01:05 MST 
Created attachment 9430 [details]
0001-mpi-pmix-select-the-Tree-based-collective-type-for-e.patch

Hello,

This patch changes the logic of selecting a type of collective. The Tree-based algorithm will be selected when fence with an empty data contribution, which allows for improved fence performance. In the other case, the ring type coll will be used.
Comment 2 Tim Wickberg 2019-04-29 14:03:26 MDT 
Hi Boris -

Thank you for the patch. This is in ahead of 19.05rc1 which will come out on Tuesday.

- Tim

commit fa5620dfd76760794d54f1be0395bf4da69339aa (HEAD -> master)
Author:     Boris Karasev <karasev.b@gmail.com>
AuthorDate: Mon Mar 4 15:14:43 2019 +0600

    mpi/pmix: use the Tree-based collective type for empty fence data.
    
    This commit changes the logic of selecting a type of collective. The
    Tree-based algorithm will be selected when fence with an empty data
    contribution, which allows for improved fence performance.
    
    Bug 6637.