Program locality of vectorized applications running on the IBM 3090 with Vector Facility
Kimming So, Vittorio Zecca · IBM Systems Journal · 1988
An instruction-level simulator is used to study the program locality of large scientific applications. The simulator, which models an IBM 3090 processor with Vector Facility and a cache, was developed to help a programmer improve the performance of an application through better understanding and use of the Vector Facility and the memory hierarchy of the IBM 3090 system. Our main observations on a set of scientific applications are as follows: (1) although the applications have different characteristics of memory accesses and vectorization , their program locality is high enough to take advantage of conventional cache structures; (2) the cache hit ratio of the vector execution can be quite different from (but not significantly lower than) that of the scalar execution of the same application; and (3) the application programs that are written to optimize the use of the memory hierarchy in the system generally result in higher cache hit ratios than the others. The cache performance of these applications with respect to various cache parameters is also presented. In particular, our study finds that the cache structure of the IBM 3090 is well suited for large scientific applications.