The on-chip 3-MB subarray-based third-level cache on an Itanium microprocessor

摘要

The 3-MB on-chip level three cache in the Itanium 2 processor, built on an 0.18-Μm, six-layer Al metal process, employs a subarray design style that efficiently utilizes available area and flexibly adapts to floor plan changes. Through a distributed decoding scheme and compact circuit design and layout, 85% array efficiency was achieved for the subarrays. In addition, various test and reliability features were included. The cache allows for a store and a load every four core cycles and has been characterized to operate above 1.2 GHz at 1.5 V and 110°C. When running at 1.0 GHz, the cache provides a total bandwidth of 64 GB/s.