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2009 IEEE International Symposium on Workload Characterization (IISWC) (2009)
Austin, TX, USA
Oct. 4, 2009 to Oct. 6, 2009
ISBN: 978-1-4244-5156-2
pp: 188-197
James Charles , Simon Fraser University, Canada
Preet Jassi , Simon Fraser University, Canada
Narayan S Ananth , Simon Fraser University, Canada
Abbas Sadat , Simon Fraser University, Canada
Alexandra Fedorova , Simon Fraser University, Canada
The Intel® Core™ i7 processor code named Nehalem has a novel feature called Turbo Boost which dynamically varies the frequencies of the processor's cores. The frequency of a core is determined by core temperature, the number of active cores, the estimated power and the estimated current consumption. We perform an extensive analysis of the Turbo Boost technology to characterize its behavior in varying workload conditions. In particular, we analyze how the activation of Turbo Boost is affected by inherent properties of applications (i.e., their rate of memory accesses) and by the overall load imposed on the processor. Furthermore, we analyze the capability of Turbo Boost to mitigate Amdahl's law by accelerating sequential phases of parallel applications. Finally, we estimate the impact of the Turbo Boost technology on the overall energy consumption. We found that Turbo Boost can provide (on average) up to a 6% reduction in execution time but can result in an increase in energy consumption up to 16%. Our results also indicate that Turbo Boost sets the processor to operate at maximum frequency (where it has the potential to provide the maximum gain in performance) when the mapping of threads to hardware contexts is sub-optimal.

A. Fedorova, J. Charles, N. S. Ananth, A. Sadat and P. Jassi, "Evaluation of the Intel," 2009 IEEE International Symposium on Workload Characterization (IISWC), Austin, TX, USA, 2009, pp. 188-197.
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