Class to provide a CPU usage indication based on task callback availability. To produce useful results it requires a couple of seconds at startup to calibrate.
Use like this:
#include <Services/Profiling/CpuUsage.h>
// instantiate a single instance of :cpp:class:`Profiling::CpuUsage`
Profiling::CpuUsage cpuUsage;
// Will be called when CpuUsage calibration has completed
void onReady()
{
// Continue with application initialisation
}
void init()
{
// Begin clock calibration
cpuUsage.begin(onReady);
}See :sample:`Basic_Tasks` for a more detailed example.
CPU usage is calculated over an update period which begins with a call to :cpp:func:`Profiling::CpuUsage::reset`. The actual update period must be managed elsewhere, using a callback timer, web request or other mechanism. It doesn't need to be exact as the actual elapsed time in CPU cycles is used for the calculation.
After the update period has elapsed, call :cpp:func:`Profiling::CpuUsage::getUtilisation` to obtain a CPU usage figure.
This figure is obtained using the number of task callbacks made within the update period.
- loop cycles
- Set up repeating task callback and measure invocations between successive calls
- total cycles
- The total number of CPU cycles between calls to :cpp:func:`Profiling::CpuUsage::update`.
- used
- total - loop
- utilisation
- used / total
.. doxygenclass:: Profiling::CpuUsage
:members: