You can estimate CPU usage in given time range, basing on available stack trace telemetry.
How to invoke
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Select arbitrary time range in telemetry graph:
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Select event(s) in probes UI, and use popup menu action:
Comparison with CPU sampling
This feature is similar to CPU sampling, as it also uses sampling approach, but there are sufficient differences:
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Comparison criteria
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CPU usage estimation
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"Real" CPU sampling
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Comments
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| Results availability | Always, as long as stack telemetry is enabled | Should be explicitly started | CPU usage estimation is ideal for analysis of anomalies such as CPU spikes, especially those which has already happened, so you do not need to turn CPU sampling or tracing on and try reproduce the spike. |
| Accuracy | Lower | Higher |
CPU usage estimation is based on thread telemetry, whose frequency is normally as low as 1 sample per second, and can increase under certain circumstances:
CPU usage estimation can adequately measure events not shorter than the thread telemetry period. So, it suits for measuring events that last several seconds, or, with increased stack telemetry frequency - at least 0.3-0.5 second. But if the event is long enough, the estimation will do its job - locate problematic code responsible for the CPU spike. For measuring shorter events or methods, use normal CPU profiling. |
| Granularity | Results are available for each particular event, as well as for entire time range | Results are aggregated for entire period of CPU profiling |
CPU usage estimation enables analysis of particular events or time ranges within single snapshot. CPU profiling results are aggregated since CPU profiling has been started. It is not possible to "extract" CPU profiling results for a smaller time range within one snapshot. (However, you can choose which method calls to analyze.) |