aa1a8ce533
Pull tracing updates from Steven Rostedt:
"New tracing features:
- The ring buffer is no longer disabled when reading the trace file.
The trace_pipe file was made to be used for live tracing and
reading as it acted like the normal producer/consumer. As the trace
file would not consume the data, the easy way of handling it was to
just disable writes to the ring buffer.
This came to a surprise to the BPF folks who complained about lost
events due to reading. This is no longer an issue. If someone wants
to keep the old disabling there's a new option "pause-on-trace"
that can be set.
- New set_ftrace_notrace_pid file. PIDs in this file will not be
traced by the function tracer.
Similar to set_ftrace_pid, which makes the function tracer only
trace those tasks with PIDs in the file, the set_ftrace_notrace_pid
does the reverse.
- New set_event_notrace_pid file. PIDs in this file will cause events
not to be traced if triggered by a task with a matching PID.
Similar to the set_event_pid file but will not be traced. Note,
sched_waking and sched_switch events may still be traced if one of
the tasks referenced by those events contains a PID that is allowed
to be traced.
Tracing related features:
- New bootconfig option, that is attached to the initrd file.
If bootconfig is on the command line, then the initrd file is
searched looking for a bootconfig appended at the end.
- New GPU tracepoint infrastructure to help the gfx drivers to get
off debugfs (acked by Greg Kroah-Hartman)
And other minor updates and fixes"
* tag 'trace-v5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (27 commits)
tracing: Do not allocate buffer in trace_find_next_entry() in atomic
tracing: Add documentation on set_ftrace_notrace_pid and set_event_notrace_pid
selftests/ftrace: Add test to test new set_event_notrace_pid file
selftests/ftrace: Add test to test new set_ftrace_notrace_pid file
tracing: Create set_event_notrace_pid to not trace tasks
ftrace: Create set_ftrace_notrace_pid to not trace tasks
ftrace: Make function trace pid filtering a bit more exact
ftrace/kprobe: Show the maxactive number on kprobe_events
tracing: Have the document reflect that the trace file keeps tracing enabled
ring-buffer/tracing: Have iterator acknowledge dropped events
tracing: Do not disable tracing when reading the trace file
ring-buffer: Do not disable recording when there is an iterator
ring-buffer: Make resize disable per cpu buffer instead of total buffer
ring-buffer: Optimize rb_iter_head_event()
ring-buffer: Do not die if rb_iter_peek() fails more than thrice
ring-buffer: Have rb_iter_head_event() handle concurrent writer
ring-buffer: Add page_stamp to iterator for synchronization
ring-buffer: Rename ring_buffer_read() to read_buffer_iter_advance()
ring-buffer: Have ring_buffer_empty() not depend on tracing stopped
tracing: Save off entry when peeking at next entry
...
Linux Ftrace Testcases
This is a collection of testcases for ftrace tracing feature in the Linux
kernel. Since ftrace exports interfaces via the debugfs, we just need
shell scripts for testing. Feel free to add new test cases.
Running the ftrace testcases
============================
At first, you need to be the root user to run this script.
To run all testcases:
$ sudo ./ftracetest
To run specific testcases:
# ./ftracetest test.d/basic3.tc
Or you can also run testcases under given directory:
# ./ftracetest test.d/kprobe/
Contributing new testcases
==========================
Copy test.d/template to your testcase (whose filename must have *.tc
extension) and rewrite the test description line.
* The working directory of the script is <debugfs>/tracing/.
* Take care with side effects as the tests are run with root privilege.
* The tests should not run for a long period of time (more than 1 min.)
These are to be unit tests.
* You can add a directory for your testcases under test.d/ if needed.
* The test cases should run on dash (busybox shell) for testing on
minimal cross-build environments.
* Note that the tests are run with "set -e" (errexit) option. If any
command fails, the test will be terminated immediately.
* The tests can return some result codes instead of pass or fail by
using exit_unresolved, exit_untested, exit_unsupported and exit_xfail.
Result code
===========
Ftracetest supports following result codes.
* PASS: The test succeeded as expected. The test which exits with 0 is
counted as passed test.
* FAIL: The test failed, but was expected to succeed. The test which exits
with !0 is counted as failed test.
* UNRESOLVED: The test produced unclear or intermidiate results.
for example, the test was interrupted
or the test depends on a previous test, which failed.
or the test was set up incorrectly
The test which is in above situation, must call exit_unresolved.
* UNTESTED: The test was not run, currently just a placeholder.
In this case, the test must call exit_untested.
* UNSUPPORTED: The test failed because of lack of feature.
In this case, the test must call exit_unsupported.
* XFAIL: The test failed, and was expected to fail.
To return XFAIL, call exit_xfail from the test.
There are some sample test scripts for result code under samples/.
You can also run samples as below:
# ./ftracetest samples/
TODO
====
* Fancy colored output :)