README.rst
1.. zephyr:code-sample:: syscall_perf
2 :name: Syscall performance
3
4 Measure performance overhead of a system calls compared to direct function calls.
5
6Syscall performances
7====================
8
9The goal of this sample application is to measure the performance loss when a
10user thread has to go through a system call compared to a supervisor thread that
11calls the function directly.
12
13
14Overview
15********
16
17This application creates a supervisor and a user thread.
18Then both threads call :c:func:`k_current_get()` which returns a reference to the
19current thread. The user thread has to go through a system call.
20
21Both threads are showing the number of core clock cycles and the number of
22instructions executed while calling :c:func:`k_current_get()`.
23
24
25Sample Output
26*************
27
28.. code-block:: console
29
30 User thread: 18012 cycles 748 instructions
31 Supervisor thread: 7 cycles 4 instructions
32 User thread: 20136 cycles 748 instructions
33 Supervisor thread: 7 cycles 4 instructions
34 User thread: 18014 cycles 748 instructions
35 Supervisor thread: 7 cycles 4 instructions
36
