CPU Profiler

Start recording a CPU profile by clicking Record.
When you are done recording, click Stop. At this point,
CPU profiling data is pulled from the VM and displayed
in the profiler views (Call Tree, Bottom Up, and Flame Chart).

Profile granularity

The default rate at which the VM collects CPU samples
is 1 sample / 250 μs.  This is selected by default on
the CPU profiler view as “Profile granularity: medium”.
This rate can be modified using the selector at the top
of the page. The sampling rates for low, medium,
and high granularity are 1 / 1000 μs, 1 / 250 μs, and 1 / 50 μs,
respectively. It is important to know the trade-offs
of modifying this setting.