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README.rst
.. _syscall_perf:
Syscall performances
====================
The goal of this sample application is to measure the performance loss when a
user thread has to go through a system call compared to a supervisor thread that
calls the function directly.
Overview
********
This application creates a supervisor and a user thread.
Then both threads call :c:func:`k_current_get()` which returns a reference to the
current thread. The user thread has to go through a system call.
Both threads are showing the number of core clock cycles and the number of
instructions executed while calling :c:func:`k_current_get()`.
Sample Output
*************
.. code-block:: console
User thread: 18012 cycles 748 instructions
Supervisor thread: 7 cycles 4 instructions
User thread: 20136 cycles 748 instructions
Supervisor thread: 7 cycles 4 instructions
User thread: 18014 cycles 748 instructions
Supervisor thread: 7 cycles 4 instructions