Software directed issue queue power reduction
Document typeConference report
PublisherInstitute of Electrical and Electronics Engineers (IEEE)
Rights accessOpen Access
All rights reserved. This work is protected by the corresponding intellectual and industrial property rights. Without prejudice to any existing legal exemptions, reproduction, distribution, public communication or transformation of this work are prohibited without permission of the copyright holder
The issue logic of a superscalar processor dissipates a large amount of static and dynamic power. Furthermore, its power density makes it a hot-spot requiring expensive cooling systems and additional packaging. In this paper we present a novel software assisted approach to power reduction where the processor dynamically resizes the issue queue based on compiler analysis. The compiler passes information to the processor about the number of entries needed which limits the number of instructions dispatched and resident in the queue. This saves power without adversely affecting performance. Compared with recently proposed hardware techniques, our approach is faster, simpler and saves more power. Using a simplistic scheme we achieve 47% dynamic and 31% static power savings in the issue queue with only a 2.2% performance loss. We then show that the performance loss can be reduced to less than 1.3% with 45% dynamic and 30% static power savings, outperforming all current approaches.
CitationJones, T. [et al.]. Software directed issue queue power reduction. A: International Symposium on High-Performance Computer Architecture (HPCA). "HPCA: The Eleventh International Symposium on High-Performance Computer Architecture: 12–16 February 2005 San Francisco, California: Proceedings". San Francisco, California: Institute of Electrical and Electronics Engineers (IEEE), 2005, p. 144-153.