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Linux Kernel Selftests
The kernel contains a set of "self tests" under the tools/testing/selftests/
directory. These are intended to be small tests to exercise individual code
paths in the kernel. Tests are intended to be run after building, installing
and booting a kernel.
On some systems, hot-plug tests could hang forever waiting for cpu and
memory to be ready to be offlined. A special hot-plug target is created
to run full range of hot-plug tests. In default mode, hot-plug tests run
in safe mode with a limited scope. In limited mode, cpu-hotplug test is
run on a single cpu as opposed to all hotplug capable cpus, and memory
hotplug test is run on 2% of hotplug capable memory instead of 10%.
Running the selftests (hotplug tests are run in limited mode)
=============================================================
To build the tests:
$ make -C tools/testing/selftests
To run the tests:
$ make -C tools/testing/selftests run_tests
To build and run the tests with a single command, use:
$ make kselftest
- note that some tests will require root privileges.
Running a subset of selftests
========================================
You can use the "TARGETS" variable on the make command line to specify
single test to run, or a list of tests to run.
To run only tests targeted for a single subsystem:
$ make -C tools/testing/selftests TARGETS=ptrace run_tests
You can specify multiple tests to build and run:
$ make TARGETS="size timers" kselftest
See the top-level tools/testing/selftests/Makefile for the list of all
possible targets.
Running the full range hotplug selftests
========================================
To build the hotplug tests:
$ make -C tools/testing/selftests hotplug
To run the hotplug tests:
$ make -C tools/testing/selftests run_hotplug
- note that some tests will require root privileges.
Install selftests
=================
You can use kselftest_install.sh tool installs selftests in default
location which is tools/testing/selftests/kselftest or an user specified
location.
To install selftests in default location:
$ cd tools/testing/selftests
$ ./kselftest_install.sh
To install selftests in an user specified location:
$ cd tools/testing/selftests
$ ./kselftest_install.sh install_dir
Contributing new tests
======================
In general, the rules for selftests are
* Do as much as you can if you're not root;
* Don't take too long;
* Don't break the build on any architecture, and
* Don't cause the top-level "make run_tests" to fail if your feature is
unconfigured.