AP_setparam

Reset the parameters that govern behavior of AUTOPACK

Synopsis

#include "autopack.h"

void AP_setparam(int size, int packed, int nwait_proc, int nwait)

SUBROUTINE AP_SETPARAM(size, packed, nwait_proc, nwait)
INTEGER size, packed, nwait_proc, nwait

Parameters

size
preferred size in bytes for memory blocks (packages)
packed
if nonzero, enable automatic packing
nwait_proc
max number of MPI sends per destination proc
nwait
max number of MPI sends for all destinations. If nwait<0, use only per-destination limit.

Return Value

None

Description

AUTOPACK parameters may be changed at any time. Changes to size or packed will affect subsequent messages but will not affect any message already allocated. Changes to nwait_proc or nwait will govern subsequent MPI sends. If the limit is reduced, no pending sends are cancelled; the limit may not be attained until some sends complete.

User advice

Size is a guideline; allocation will be made larger if necessary. If it is too small, you will end up with one message per package/memory block. Setting it too large will waste memory and reduce potential overlap of computation/communication.