Program optimization for a pipelined machine a case study

The Amdahl 580 processor is a pipelined processor whose performance can be affected by characteristics of the instructions it executes. This paper describes certain optimizations made to a set of system software routines during their development. The optimization effort was driven by the execution frequencies of common paths through the programs in question, and by the execution characteristics of those paths, as shown by a processor simulator. Path optimization itself was done with both general program optimization techniques and with techniques specific to the particular characteristics of the 580's pipeline. Overall, the average execution time for these routines was reduced by over 50%.