About cookies on this site Our websites require some cookies to function properly (required). In addition, other cookies may be used with your consent to analyze site usage, improve the user experience and for advertising. For more information, please review your options. By visiting our website, you agree to our processing of information as described in IBM’sprivacy statement. To provide a smooth navigation, your cookie preferences will be shared across the IBM web domains listed here.
Publication
LPED 2002
Conference paper
Saving energy with just in time instruction delivery
Abstract
Just-In-Time instruction delivery is a general method for saving energy in a microprocessor by dynamically limiting the number of in-flight instructions. The goal is to save energy by 1) fetching valid instructions no sooner than necessary, avoiding cycles stalled in the pipeline - especially the issue queue, and 2) reducing the number of fetches and subsequent processing of mis-speculated instructions. A simple algorithm monitors performance and adjusts the maximum number of in-flight instructions at fairly long intervals, 100K instructions in this study. The proposed JIT instruction delivery scheme provides the combined benefits of more targeted schemes proposed previously. With only a 3% performance degradation, energy savings in the fetch, decode pipe, and issue queue are 10%, 12%, and 40%, respectively.