Namhyung Kim ce1ac64b93 ftracetest: Clear trace buffer after running kprobe testcases
The kprobe testcases create, use and delete dynamic events during the
test but didn't clear the trace buffer so it'll leave the result after
it finishes.

  # ./ftracetest
  ...

  # cat trace
  # tracer: nop
  #
  # entries-in-buffer/entries-written: 2/2   #P:12
  #
  #                              _-----=> irqs-off
  #                             / _----=> need-resched
  #                            | / _---=> hardirq/softirq
  #                            || / _--=> preempt-depth
  #                            ||| /     delay
  #           TASK-PID   CPU#  ||||    TIMESTAMP  FUNCTION
  #              | |       |   ||||       |         |
        ftracetest-26474 [009] d..1 79417.143782: Unknown type 1099
        ftracetest-26498 [009] d..1 79417.208034: Unknown type 1101

Link: http://lkml.kernel.org/r/1415239470-28705-2-git-send-email-namhyung@kernel.org

Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-11-06 08:39:39 -05:00
..
2014-05-12 00:23:55 -04:00
2013-07-03 16:08:07 -07:00

Linux Kernel Selftests

The kernel contains a set of "self tests" under the tools/testing/selftests/
directory. These are intended to be small unit tests to exercise individual
code paths in the 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

- note that some tests will require root privileges.

To run only tests targeted for a single subsystem: (including
hotplug targets in limited mode)

  $  make -C tools/testing/selftests TARGETS=cpu-hotplug run_tests

See the top-level tools/testing/selftests/Makefile for the list of all possible
targets.

Running the full range hotplug selftests
========================================

To build the tests:

  $ make -C tools/testing/selftests hotplug

To run the tests:

  $ make -C tools/testing/selftests run_hotplug

- note that some tests will require root privileges.

Contributing new tests
======================

In general, the rules for 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.