CPU sampling settings

CPU sampling settings allow to customize some aspects of CPU sampling.

CPU tracing settings are specified separately, as described here.

When the settings are applied

The settings are applied each time you start CPU sampling. This means you can change the settings without restarting the profiled application.

To configure CPU sampling settings use Settings | CPU Sampling... in the main menu.

The settings are also accessible via a link in the CPU profiling toolbar popup:

The following dialog appears:

Configurable properties:

Time measurement

Specify whether CPU or wall time will be measured for profiled methods by using the time property.

By default, CPU time is measured which corresponds to the option time=cpu.

With synchronous and asynchronous periodic sampling, it's possible to measure wall time instead by using time=wall.

Asynchronous CPU sampling always measures CPU time, the time property value is ignored.

When starting sampling from the profiler UI, choose the option via Use Preconfigured Settings... or manually edit the property value.
Sampling period (synchronous and asynchronous periodic sampling)

Specify how often samples are taken with sampling_period_ms=<time in milliseconds>. By default, samples are taken each 20 milliseconds (sampling_period_ms=20).
CPU threshold (asynchronous CPU sampling)

Specify CPU time threshold for asynchronous CPU sampling with cpu_threshold_ms=<time in milliseconds>. By default, CPU time threshold is 10 milliseconds.

The settings are stored in the file

<user home>/.yjp/sampling_2022.txt

where user home corresponds to the account under which a profiled application is launched.

This file is automatically updated in your user home directory when you apply changes in the UI (see above).

You can edit this file manually, but note that it may be fully overwritten with Use Preconfigured Settings... in UI.

The settings file is read and applied when CPU sampling is started with:

API methods Controller.startSampling*(null)
HTTP API with absent settings
trigger actions StartSampling, StartAsyncSamplingCpu, StartAsyncSamplingPeriodic

You can specify a custom settings file for a particular application by using the startup option sampling_settings_path