Copyright by William Lloyd Bircher 2010 - The Laboratory for ...

6.2.1 Power and Performance Results
In this section results for p-state and c-state settings are presented that reflect the findings
of the previous sections. In this case the Microsoft Windows Vista operating system
running desktop workloads is studied. This approach gives the highest exposure to the
effect the operating system has on dynamic adaptations. By choosing desktop workloads,
the number of phase transitions and, therefore, OS interaction is increased. Since these
workloads model user input and think times, idle phases are introduced. These idle
phases are required for OS study since the OS makes use of idle time for selecting the
operating point. Also, Microsoft Windows Vista exposes tuning parameters to scale the
built-in adaptation selection algorithms for power savings versus performance. Table 6.2
shows power and performance results for SYSmark 2007 using a range of settings chosen
based on the results of the previous sections.
Table 6.2 Power/Performance Study: SYSmark 2007
Workload P-State Selection Performance Loss Power Savings
E-Learning Default 8.8% 43.1%
Video Creation Default 6.2% 44.7%
Productivity Default 9.5% 45.3%
3D Default 5.9% 45.9%
E-Learning Fast 6.4% 45.9%
Video Creation Fast 5.2% 46.1%
Productivity Fast 8.0% 47.8%
3D Fast 4.6% 48.2%
E-Learning Fast-Perf 1.5% 32.9%
Video Creation Fast-Perf 1.8% 25.4%
Productivity Fast-Perf 2.5% 27.9%
3D Fast-Perf 1.4% 35.1%
116