edits (todos)
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@ -68,7 +68,7 @@ For example, in memory-bound workloads (i.e., with frequent CPU stalls resulting
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}.
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By comparison, tasks blocked on IO or user input are removed from the runqueue entirely, allowing the CPU to enter an idle state.
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\todo{add an experiment that shows that tasks blocked on IO or user input or something similar have similar energy profiles.?}
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%\todo{add an experiment that shows that tasks blocked on IO or user input or something similar have similar energy profiles.?}
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We note that CPU utilization is a measure of time spent idling or blocked on IO, and not the time the CPU spends running without doing useful work, supporting our second claim:
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\claim{
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@ -89,9 +89,8 @@ We tracked the time spent for each CPU at a given frequency, with 0 representing
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The solid blue lines in the top 2 graphs are histograms of the average time spent at each speed for little and big CPUs.
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The dashed red lines provides a baseline of a governor that selects a fixed 70\% CPU frequency ($\approx \fenergy$) for the CPU when work is pending (and as usual, that idles the core when no work is available).
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Note that, when the CPU is idle, depicted by a speed of 0, the actual and baseline plots coincide.
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The left-side grey shaded regions show that the app spends significant \textit{non-idle} time running at speeds below $\fenergy$ -- approximately 2/3 for little CPUs and 1/4 for big CPUs.
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All of the time spent in the left-side grey areas represents energy wasted for a slower performance.
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\todo{cut the references to grey boxes if the boxes are cut}
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The left-sides of the 2 CDF plots (bottom 2 graphs of Figure \ref{fig:time_per_freq_fb}) show that the app spends significant \textit{non-idle} time running at speeds below $\fenergy$ -- approximately 2/3 for little CPUs and 1/4 for big CPUs.
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All of the time spent in the areas marked Underperformance represents energy wasted for a slower performance.
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\begin{figure*}
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\centering
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