This variable enables the runtime to perform address optimizations on each Linkage item individually. In versions prior to 8.1 this optimization was done either for all Linkage items or for none of them, which could result in scenarios where optimizations could have occurred on some items, but did not.

The default and recommended setting is 1 (on) because the main effect is improved CALL performance in a greater number of scenarios. Usually, the only reason to turn this variable off is if a flaw is suspected in the optimization.