Compaq W8000 Hyper-Threading Technology, New Feature of Intel Xeon Processor - Page 3

Hyper-Threading Technology, New Feature of Intel Xeon Processor White Paper 3 Introduction The Compaq Evo Workstations W6000 and W8000 incorporate the new leading-edge Intel Xeon Multi-processor (MP) processor and the Intel i860 chipset to achieve the next level of system performance. The purpose of this paper is to explain the impacts on processor performance with the new Intel Hyper-Threading (HT) technology enabled versus disabled in Compaq Evo Workstations W6000 and W8000. The performance of the system is directly related to Instructions Per Clock (IPC). The two ways to increase system performance today are the following. • The operating system (OS) of multi-processor (MP) system configurations, such as Microsoft Windows NT, Windows 2000, Windows XP and any later OS that supports MP, take advantage of Thread Level Parallelism (TLP). These operating systems divide their workloads into processes and threads, which can be independently scheduled and dispatched to run on the processors that are idle or available. Note: Microsoft Windows 98 and Microsoft ME do not support multiple processors. • Instruction Level Parallelism (ILP) increases the IPC. Very Long Instruction Word (VLIW) and Explicitly Parallel Instruction-set Computing (EPIC) are designed from the ground up to support IPC. However, these instructions do not maintain binary compatibility with the Intel Architecture (IA), known as the IA-32 Instruction-set. Hyper-Threading Technology Intel has developed a new feature called Hyper-Threading technology for the IA-32 architecture, which provides a performance boost to the processors. Hyper-Threading technology signals a fundamental shift in processor design. The multi-threading design techniques allow an OS to view a single physical processor as if it were two logical processors. To accomplish this, processors enabled with Hyper-Threading technology can manage incoming tasks from different software applications and continuously alternate from one task to the other, without losing track of the data processing status of each task. Current processor technologies queue up individual instructions and handle them one at a time in a logical order (out of order execution, in-order retirement), much like a person who is trying to watch television while talking on the phone. In the current scenario, the person takes in data from each medium, handling it piece by piece. Hyper-Threading technology allows the viewer to accomplish both activities simultaneously without impacting the quality or speed of either experience. Advantages Some of the advantages of Hyper-Threading technology include the following: • Improved overall system performance • Increased number of users that a platform can support (server applications) • Improved reaction and response time because tasks can be run on separate threads • Increased number of transactions that can be executed 167T-0202A-WWEN