Dark silicon and the end of multicore scaling
- 4 June 2011
- journal article
- conference paper
- Published by Association for Computing Machinery (ACM) in ACM SIGARCH Computer Architecture News
- Vol. 39 (3), 365-376
- https://doi.org/10.1145/2024723.2000108
Abstract
Since 2005, processor designers have increased core counts to exploit Moore's Law scaling, rather than focusing on single-core performance. The failure of Dennard scaling, to which the shift to multicore parts is partially a response, may soon limit multicore scaling just as single-core scaling has been curtailed. This paper models multicore scaling limits by combining device scaling, single-core scaling, and multicore scaling to measure the speedup potential for a set of parallel workloads for the next five technology generations. For device scaling, we use both the ITRS projections and a set of more conservative device scaling parameters. To model single-core scaling, we combine measurements from over 150 processors to derive Pareto-optimal frontiers for area/performance and power/performance. Finally, to model multicore scaling, we build a detailed performance model of upper-bound performance and lower-bound core power. The multicore designs we study include single-threaded CPU-like and massively threaded GPU-like multicore chip organizations with symmetric, asymmetric, dynamic, and composed topologies. The study shows that regardless of chip organization and topology, multicore scaling is power limited to a degree not widely appreciated by the computing community. Even at 22 nm (just one year from now), 21% of a fixed-size chip must be powered off, and at 8 nm, this number grows to more than 50%. Through 2024, only 7.9x average speedup is possible across commonly used parallel workloads, leaving a nearly 24-fold gap from a target of doubled performance per generation.Keywords
This publication has 19 references indexed in Scilit:
- Conservation coresPublished by Association for Computing Machinery (ACM) ,2010
- Many-Core vs. Many-Thread Machines: Stay Away From the ValleyIEEE Computer Architecture Letters, 2009
- The PARSEC benchmark suitePublished by Association for Computing Machinery (ACM) ,2008
- Amdahl's Law in the Multicore EraComputer, 2008
- Corollaries to Amdahl's Law for EnergyIEEE Computer Architecture Letters, 2008
- An Asymptotic Performance/Energy Analysis and Optimization of Multi-core ArchitecturesLecture Notes in Computer Science, 2008
- Core fusionPublished by Association for Computing Machinery (ACM) ,2007
- Thousand core chipsProceedings of the 39th conference on Design automation - DAC '02, 2007
- Design of ion-implanted MOSFET's with very small physical dimensionsIEEE Journal of Solid-State Circuits, 1974
- Validity of the single processor approach to achieving large scale computing capabilitiesPublished by Association for Computing Machinery (ACM) ,1967