zephyr/tests/benchmarks/sched_userspace
Keith Packard 0b90fd5adf samples, tests, boards: Switch main return type from void to int
As both C and C++ standards require applications running under an OS to
return 'int', adapt that for Zephyr to align with those standard. This also
eliminates errors when building with clang when not using -ffreestanding,
and reduces the need for compiler flags to silence warnings for both clang
and gcc.

Most of these changes were automated using coccinelle with the following
script:

@@
@@
- void
+ int
main(...) {
	...
-	return;
+	return 0;
	...
}

Approximately 40 files had to be edited by hand as coccinelle was unable to
fix them.

Signed-off-by: Keith Packard <keithp@keithp.com>
2023-04-14 07:49:41 +09:00
..
src
CMakeLists.txt
prj.conf
README.rst
testcase.yaml

Userspace Scheduler Microbenchmark
##################################

This is a scheduler microbenchmark, designed to measure minimum
latencies (not scaling performance) of specific low level scheduling
primitives independent of overhead from application or API
abstractions. Contrary to the non-userspace version, it runs threads
in userspace with different memory domains.

 It works very simply: a main thread creates n "yielders"
threads at a higher priority, from this initial state:

1. The main thread starts all yielders
2. Each yielder yields k times
5. The main thread joins all yielders

This is run for multiples values of n, reporting each time the
average time taken for a yield context switch.