User Guide

Contents

Interpret Energy Analysis Data with
Intel® VTune™
Profiler

Identify causes of energy waste on target systems by opening your energy analysis results with
Intel VTune
Profiler
.
Collecting energy analysis data with Intel® SoC Watch is available for target Android*, Windows*, or Linux* devices and provided only with the Intel System Studio. Import and viewing of the Intel SoC Watch results is supported with any version of the VTune
Profiler
.
After you collect energy analysis data on your target system, using the Intel® SoC Watch collector, you can import a result file (
*.pwr
) to
Intel® VTune™
Profiler
on your host system. Energy analysis data is opened in the Platform Power analysis viewpoint.
To interpret the performance data provided during the energy analysis, you may follow the steps below:

Analyze Overall Statistics

Use the Summary window to view statistics on the overall collection run time execution per power analysis metrics. Viewing the top statistics and histograms for a particular metric is a good starting point. Focus on decreasing the causes of core wake-up and increasing the time that the core spends in the higher sleep states.
For example, this
Top Core C-State by State
diagram shows that the core was awake for approximately 10 seconds of the total collection time (time in CC0 state). Use the
Profiled Entity
drop-down to view the C-state data for other cores. Explore the histogram to analyze the time spent in each sleep state.
Elapsed Time per CPU Sleep State Histogram
Click the
Details
link next to the table or graph title on the
Summary
tab to view more information about that metric in another tab.

Identify Cores with Highest Time Spent in C0 States

Switch to the C-State Residency/Wakeups window and the Core C-State tab to identify cores with the highest time spent in the active C0 state. Spending more time in deeper sleep states (C1-Cn) provides greater power savings.
By default,
VTune
Profiler
displays data grouped by core and sorted by CPU time spent in the deepest C-state in the ascending order. For the example below, over 30% of the time was spent in the CC0 active state for both cores.
CPU Sleep States Viewpoint: CPU Sleep States Pane
Use the timeline view to understand when state transitions occur. Hover over a chart point to view the sleep states details for the particular moment of time. The deeper the color of the chart, the deeper the sleep state of the CPU. Select a region of the graph and zoom into the selection to see detailed sleep state transitions.

Product and Performance Information

1

Intel's compilers may or may not optimize to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include SSE2, SSE3, and SSSE3 instruction sets and other optimizations. Intel does not guarantee the availability, functionality, or effectiveness of any optimization on microprocessors not manufactured by Intel. Microprocessor-dependent optimizations in this product are intended for use with Intel microprocessors. Certain optimizations not specific to Intel microarchitecture are reserved for Intel microprocessors. Please refer to the applicable product User and Reference Guides for more information regarding the specific instruction sets covered by this notice.

Notice revision #20110804