Reorder buffer structure with shelter buffer for out-of-order issue superscalar processors

초록

In this paper, we propose a reorder buffer structure with shelter buffer in out-of-order issue superscalar processors not only to control stagnation efficiently, but also to reduce the size of reorder buffer. The reorder buffer is usually employed to complete the execution in order for out-of-order issued instructions. We can get performance improvement with a small size of shelter buffers. If a processor has one floating-point unit, the throught is improved by 78% at its maximum, and if unlimited number of execution units is employed, the throughput is improved by 228%. If the size of a reorder buffer is less than 8, the reorder buffer with one shelter buffer has better performance than the one with two shelter buffers under the condition that total size of the two buffers is the same. However, with reorder buffer sizes bigger than 16, reorder buffers using two shelter buffers always give better performance.