User and Reference Guide

Contents

Buffer Given to MPI Cannot Be Read or Written

(LOCAL:MEMORY:INACCESSIBLE)
During the check for
LOCAL:MEMORY:ILLEGAL_MODIFICATION
of a send buffer Intel® Trace Collector will read each byte in the buffer once. This works for contiguous as well as non-contiguous data types. If any byte cannot be read because the memory is inaccessible, a
LOCAL:MEMORY:INACCESSIBLE
is reported. This is an error because it is only possible to proceed by skipping the entire operation.
Disabling the
LOCAL:MEMORY:ILLEGAL_MODIFICATION
check also disables the accessibility check and send operations are then treated like receive operations: for receive operations no similar check is performed because the MPI standard does not say explicitly that the whole receive buffer has to be accessible - only the part into which an incoming message actually gets copied must be writable. Violations of that rule are caught and reported as fatal
LOCAL:EXIT:SIGNAL
errors.

Product and Performance Information

1

Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.