Jerome C. Huck

Architectural support for translation table management in large address space machines

Virtual memory page translation tables provide mappings from virtual to physical addresses. When the hardware controlled Translation Lookaside Buffers (TLBs) do not contain a translation, these tables provide the translation. Approaches to the structure and management of these tables vary from full hardware implementations to complete software based algorithms. The size of the virtual address space used by processes is rapidly growing beyond 32 bits of address. As the utilized address space increases, new problems and issues surface. Traditional methods for managing the page translation tables are inappropriate for large address space architectures. The Hashed Page Table (HPT), described here, provides a very fast and space efficient translation table that reduces overhead by splitting TLB management responsibilities between hardware and software. Measurements demonstrate its applicability to a diverse range of operating systems and workloads and, in particular, to large virtual address space machines. In simulations of over 4 billion instructions, improvement of 5 to 10% were observed.

Introducing the IA-64 architecture

Microprocessors continue on the relentless path to provide more performance. Every new innovation in computing-distributed computing on the Internet, data mining, Java programming, and multimedia data streams-requires more cycles and computing power. Even traditional applications such as databases and numerically intensive codes present increasing problem sizes that drive demand for higher performance. Design innovations, compiler technology, manufacturing process improvements, and integrated circuit advances have been driving exponential performance increases in microprocessors. To continue this growth in the future, Hewlett Packard and Intel architects examined barriers in contemporary designs and found that instruction-level parallelism (ILP) can be exploited for further performance increases. This article examines the motivation, operation, and benefits of the major features of IA-64. Intels IA-64 manual provides a complete specification of the IA-64 architecture.

64-bit and multimedia extensions in the PA-RISC 2.0 architecture

This paper describes the architectural extensions to the PA-RISC 1.1 architecture to enable 64-bit processing of integers and pointers. It also describes MAX, the Multi-media Acceleration eXtensions which speed up the processing of multimedia and other applications with parallelism at the intra instruction, or subword, level. Other additions to the PA-RISC 2.0 architecture include performance enhancements with respect to memory hierarchy management, branch penalty reduction, and floating-point performance.