Processor-level dynamic thermal management techniques have long targeted
worst-case thermal margins. We examine the thermal-performance
trade-offs in average-case, preventive thermal management by actively
degrading application performance to achieve long-term thermal control.
We propose Dimetrodon, the use of idle cycle injection, a flexible,
per-thread technique, as a preventive thermal management mechanism and
demonstrate its efficiency compared to hardware techniques in a
commodity operating system on real hardware under throughput and
latency-sensitive real-world workloads. Compared to hardware techniques
that also lack flexibility, Dimetrodon achieves favorable trade-offs
for temperature reductions up to 30% due to rapid heat dissipation during
short idle intervals.