Open this publication in new window or tab >>2020 (English)In: 2020 IEEE International Symposium on High Performance Computer Architecture (HPCA), 2020, p. 424-434Conference paper, Published paper (Refereed)
Abstract [en]
Flexible instruction scheduling is essential for performance in out-of-order processors. This is typically achieved by using CAM-based Instruction Queues (IQs) that provide complete flexibility in choosing ready instructions for execution, but at the cost of significant scheduling energy.
In this work we seek to reduce the instruction scheduling energy by reducing the depth and width of the IQ. We do so by classifying instructions based on their readiness and criticality, and using this information to bypass the IQ for instructions that will not benefit from its expensive scheduling structures and delay instructions that will not harm performance. Combined, these approaches allow us to offload a significant portion of the instructions from the IQ to much cheaper FIFO-based scheduling structures without hurting performance. As a result we can reduce the IQ depth and width by half, thereby saving energy.
Our design, Delay and Bypass (DNB), is the first design to explicitly address both readiness and criticality to reduce scheduling energy. By handling both classes we are able to achieve 95% of the baseline out-of-order performance while only using 33% of the scheduling energy. This represents a significant improvement over previous designs which addressed only criticality or readiness (91%/89% performance at 74%/53% energy).
Series
International Symposium on High-Performance Computer Architecture-Proceedings, ISSN 1530-0897, E-ISSN 2378-203X
National Category
Computer Sciences
Identifiers
urn:nbn:se:uu:diva-403674 (URN)10.1109/HPCA47549.2020.00042 (DOI)000531494100032 ()978-1-7281-6149-5 (ISBN)
Conference
The 26th IEEE International Symposium on High-Performance Computer Architecture (HPCA), Feb. 22-26, 2020, San Diego, CA, USA
Note
As originally published there was an error in the document's author byline. The order was intended to be: Mehdi Alipour (Uppsala University); Rakesh Kumar (Norwegian University of Science and Technology (NTNU)); Stefanos Kaxiras and David Black-Schaffer (Uppsala University), as noted here. The article PDF remains unchanged.
2020-02-022020-02-022020-06-17Bibliographically approved