Dear All,
Next feed back is about MPI_Gather problem.
Gather may be truncated in following condition:
1:ompi_coll_tuned_gather_intra_linear_sync is called.
(message size is over 6000B)
2:Either send data type or recv data type is derived type and
other data type is predefined data type.
Truncated is occurred by attached C file(following output).
Output:
*** An error occurred in MPI_Gather
*** on communicator MPI_COMM_WORLD
*** MPI_ERR_TRUNCATE: message truncated
*** MPI_ERRORS_ARE_FATAL (your MPI job will now abort)
In this C program,
"first_segment_count(variable in ompi_coll_tuned_gather_intra_linear_sync)" is
different between root and non-root.
That makes messages truncated.
"first_segment_size" can not be dividable by derived data type's size,
but can dividable by predefined data type's size.
But we don't solve this problem.
So, we don't choose linear_sync in coll_tuned_decision_fixed.c.
Best Regards,
Yuki MATSUMOTO
MPI development team,
Fujitsu
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