Streamlined on-Chip Temporal Prefetching

In this paper, we present the Streamline temporal prefetcher, which introduces a stream-based metadata representation that produces three significant benefits over Triangel, the previous state-of-the-art in temporal prefetching. First, it removes redundancy present in Triangel's metadata. Second, it prioritizes the storage of those metadata entries that have higher prefetch utility. Third, it eliminates the need for the untenable LLC traffic that is induced when Triangel dynamically adjusts the size of its metadata store. The end result is that for memory-intensive SPEC 2006, SPEC 2017, and GAP benchmarks, Streamline outperforms Triangel by 6.7 percentage points on an 8-core system with a stride prefetcher. This performance benefit comes from Streamline's improved storage efficiency: It holds 33% more correlations than Triangel, which translates to$\mathbf{1 2. 5}$percentage points better prefetch coverage. Significantly, Streamline matches the performance of Triangel even when Triangel is given twice the metadata storage.