Power and Energy Characterization of an Open Source 25-core Manycore Processor Michael McKeown, Alexey Lavrov, Mohammad Shahrad, Paul J. Jackson, Yaosheng Fu∗, Jonathan Balkind, Tri M. Nguyen, Katie Lim, Yanqi Zhouy, David Wentzlaff Princeton University fmmckeown,alavrov,mshahrad,pjj,yfu,jbalkind,trin,kml4,yanqiz,
[email protected] ∗ Now at NVIDIA y Now at Baidu Abstract—The end of Dennard’s scaling and the looming power wall have made power and energy primary design CB Chip Bridge (CB) PLL goals for modern processors. Further, new applications such Tile 0 Tile 1 Tile 2 Tile 3 Tile 4 as cloud computing and Internet of Things (IoT) continue to necessitate increased performance and energy efficiency. Manycore processors show potential in addressing some of Tile 5 Tile 6 Tile 7 Tile 8 Tile 9 these issues. However, there is little detailed power and energy data on manycore processors. In this work, we carefully study Tile 10 Tile 11 Tile 12 Tile 13 Tile 14 detailed power and energy characteristics of Piton, a 25-core modern open source academic processor, including voltage Tile 15 Tile 16 Tile 17 Tile 18 Tile 19 versus frequency scaling, energy per instruction (EPI), memory system energy, network-on-chip (NoC) energy, thermal charac- Tile 20 Tile 21 Tile 22 Tile 23 Tile 24 teristics, and application performance and power consumption. This is the first detailed power and energy characterization of (a) (b) an open source manycore design implemented in silicon. The Figure 1. Piton die, wirebonds, and package without epoxy encapsulation open source nature of the processor provides increased value, (a) and annotated CAD tool layout screenshot (b).