Copyright by William Lloyd Bircher 2010 - The Laboratory for ...
Copyright by William Lloyd Bircher 2010 - The Laboratory for ...
Copyright by William Lloyd Bircher 2010 - The Laboratory for ...
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Vardan [MaVa04] per<strong>for</strong>m a subsystem level power study of a Pentium M laptop. <strong>The</strong>y<br />
present average power results <strong>for</strong> productivity workloads. In contrast, this dissertation<br />
considers a server-class SMP running a commercial workload. Feng [FeGe05-1]<br />
per<strong>for</strong>ms a study on a large clustered system running a scientific workload. As part of a<br />
proposed resource management architecture, Chase [ChAn01] presents power behavior at<br />
the system level. Lacking in all of these studies is a consideration of power phase<br />
duration. Duration is a critical aspect since it directs power adaptions. An effective<br />
adaptation scheme must choose adaptations that are appropriate to the expected duration<br />
of the event. For example, since there is a per<strong>for</strong>mance and energy cost associated with<br />
DVFS, changes to voltage/frequency should only be per<strong>for</strong>med if the system can<br />
amortize those costs be<strong>for</strong>e the next change is required.<br />
8.3 Predictive Power Adaptation<br />
While most existing power management schemes are reactive, there are a few related<br />
proposals that use predictive power management [IsBu06] [DuCa03] [DiSo08]. Isci<br />
[IsBu06] uses table-based predictors of memory operations/instruction, to direct DVFS<br />
decisions <strong>for</strong> single-threaded workloads. Duesterwald et al. [DuCa03] examine table-<br />
based predictor techniques to predict per<strong>for</strong>mance-related metrics (IPC, cache<br />
misses/instruction and branch misprediction rates) of single-thread workloads, but not<br />
power. Diao [DiSo08] uses machine learning to predict activity patterns. <strong>The</strong><br />
predictions are used to make policy decisions <strong>for</strong> entering core idle states. In contrast the<br />
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