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  1. ROOT
  2. ROOT-9979

[DF] Wrong entry ranges deduced in MT runs when nClusters >> nThreads

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    Details

    • Type: Bug
    • Status: Closed (View Workflow)
    • Priority: Blocker
    • Resolution: Fixed
    • Affects Version/s: 6.18/00
    • Fix Version/s: 6.18/00, 6.16/02
    • Component/s: None
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    • Environment:

      any

      Description

      The problem only affects the master branch.

      Reading a TTree with 184 clusters with RDF and implicit multi-threading enabled results in wrong entry ranges being distributed to tasks. In particular, ranges with start > end are created that result in exceedingly long runs which loop over wrong data.

      This is due to the recently-added logic that merges clusters together in case nClusters >> nThreads (TTreeProcessorMT.cxx lines 100-140).

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              • Assignee:
                dpiparo Danilo Piparo
                Reporter:
                eguiraud Enrico Guiraud
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