Temperature Aware Task Scheduling in MPSoCs

Ayşe Kivilcim Coşkun, Computer Science and Engineering Department, University of California, San Diego

Abstract: In deep submicron circuits, thermal hot spots and temperature variations have brought new challenges in reliability, performance, cooling costs and leakage power. Conventional thermal management sacrifices performance to control the thermal behavior by slowing down or stalling the processors when a critical temperature threshold is exceeded. Moreover, such techniques do not target minimizing the temporal and spatial variations in temperature, which impact system reliability adversely. In our work, we explore the benefits of low-overhead temperature-aware task scheduling for multiprocessor systems-on-a-chip (MPSoC).

We first establish a baseline for dynamic scheduling techniques by solving the task scheduling problem statically using integer linear programming (ILP). We then design and evaluate OS-level dynamic scheduling policies with negligible performance overhead. We show that, using simple-to-implement scheduling policies that make decisions based on real time temperature measurements, frequency of high-magnitude thermal cycles and spatial gradients can be decreased significantly, in comparison to state-of-the-art schedulers. We also enhance reactive thermal management strategies such as dynamic thread migration with our scheduling policies. This way, hot spots and temperature variations are further decreased, while the performance overhead is considerably reduced.

About the speaker: Ayşe Kivilcim Coşkun received her B.S. degree in Microelectronics Engineering from Sabanci University, Turkey in 2003, with a minor degree in Physics. Currently she is a PhD student in Computer Science and Engineering Department of University of California San Diego (UCSD) since September 2003. Kivilcim's research interests include fault tolerance in deep sub-micron and nano-scale devices, reliability and power management trade-offs and computer architecture. Her advisor in UCSD is Tajana Simunic-Rosing.

Kivilcim is also an intern at Sun Microsystems, San Diego since June 2006.