“Prefetching” is a technique that leverages predictable address patterns to speculatively bring in additional cache lines when a particular cache line is accessed. One example of prefetching is a stream buffer that prefetches sequentially adjacent cache lines into a separate buffer when a particular cache line is brought in. If the data is found in the prefetch buffer, it is considered as a hit and moved into the cache and the next cache line is prefetched. Assume a two-entry stream buffer and assume that the cache latency is such that a cache line can be loaded before the computation on the previous cache line is completed. What is the miss rate for the address stream above?

Media applications that play audio or video files are part of a class of workloads called “streaming” workloads; i.e., they bring in large amounts of data but do not reuse much of it. Consider a video streaming workload that accesses a 512 KB working set sequentially with the following address stream:

0, 2, 4, 6, 8, 10, 12, 14, 16, ...