CONTRIBUTION TO PERFORMANCE OF INSTRUCTION SET USAGE IN SYSTEM/370.

Abstract

The actual usage of instructions in the different environments in which a processor must run reflect both architectural and work-load considerations, while the achieved overall internal-processor performance reflects these as well as processor implementation considerations. The most frequently used instructions are not necessarily those which the processor spends the most time executing, either totally or on a per-instruction basis. Furthermore, focusing on the effects of instruction usage in one environment may provide an inadequate basis for projecting the effects in other environments. This is illustrated by measurements of production systems executing on large IBM mainframe processors. A significant aspect is the differentiation between supervisor and problem program instruction usage, and the extent of their commonality across environments.