perf docs: Fix format of unordered lists

Fix the format of unordered lists so the can wrap properly.

Signed-off-by: Changbin Du <changbin.du@huawei.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20230718085242.3090797-1-changbin.du@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf ftrace latency: Update documentation

Add description of 'perf ftrace latency' subcommand.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Changbin Du <changbin.du@gmail.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: https://lore.kernel.org/r/20220321234609.90455-2-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf tools: Fix documentation of verbose options

Option doesn't take a value, make sure the man pages agree. For example:

$ perf evlist --verbose=1
Error: option `verbose' takes no value

Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20210226183145.1878782-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf: ftrace: Add filter support for option -F/--funcs

Same as 'perf probe -F', this patch adds filter support for the ftrace
subcommand option '-F, --funcs <[FILTER]>'.

Here is an example that only lists functions which start with 'vfs_':

$ sudo perf ftrace -F vfs_*
vfs_fadvise
vfs_fallocate
vfs_truncate
vfs_open
vfs_setpos
vfs_llseek
vfs_readf
vfs_writef
...

Suggested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Changbin Du <changbin.du@gmail.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20200904152357.6053-1-changbin.du@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf ftrace: Add option --tid to filter by thread id

This allows us to trace single thread instead of the whole process.

Signed-off-by: Changbin Du <changbin.du@gmail.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: http://lore.kernel.org/lkml/20200808023141.14227-17-changbin.du@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf ftrace: Add option -D/--delay to delay tracing

This adds an option '-D/--delay' to allow us to start tracing some times
later after workload is launched.

Signed-off-by: Changbin Du <changbin.du@gmail.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: http://lore.kernel.org/lkml/20200808023141.14227-16-changbin.du@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf: ftrace: Allow set graph depth by '--graph-opts'

This is to have a consistent view of all graph tracer options.
The original option '--graph-depth' is marked as deprecated.

Signed-off-by: Changbin Du <changbin.du@gmail.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: http://lore.kernel.org/lkml/20200808023141.14227-15-changbin.du@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf ftrace: Add support for trace option tracing_thresh

This adds an option '--graph-opts thresh' to setup trace duration
threshold for funcgraph tracer.

$ sudo ./perf ftrace -G '*' --graph-opts thresh=100
3) ! 184.060 us | } /* schedule */
3) ! 185.600 us | } /* exit_to_usermode_loop */
2) ! 225.989 us | } /* schedule_idle */
2) # 4140.051 us | } /* do_idle */

Signed-off-by: Changbin Du <changbin.du@gmail.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: http://lore.kernel.org/lkml/20200808023141.14227-14-changbin.du@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf ftrace: Add option 'verbose' to show more info for graph tracer

Sometimes we want ftrace display more and longer information about the
trace.

$ sudo perf ftrace -G '*'
2) 0.979 us | mutex_unlock();
2) 1.540 us | __fsnotify_parent();
2) 0.433 us | fsnotify();

$ sudo perf ftrace -G '*' --graph-opts verbose
14160.770883 | 0) <...>-47814 | .... | 1.289 us | mutex_unlock();
14160.770886 | 0) <...>-47814 | .... | 1.624 us | __fsnotify_parent();
14160.770887 | 0) <...>-47814 | .... | 0.636 us | fsnotify();
14160.770888 | 0) <...>-47814 | .... | 0.328 us | __sb_end_write();
14160.770888 | 0) <...>-47814 | d... | 0.430 us | fpregs_assert_state_consistent();
14160.770889 | 0) <...>-47814 | d... | | do_syscall_64() {
14160.770889 | 0) <...>-47814 | .... | | __x64_sys_close() {

Signed-off-by: Changbin Du <changbin.du@gmail.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: http://lore.kernel.org/lkml/20200808023141.14227-13-changbin.du@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf ftrace: Add support for tracing option 'irq-info'

This adds support to display irq context info for function tracer. To do
this, just specify a '--func-opts irq-info' option.

Signed-off-by: Changbin Du <changbin.du@gmail.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: http://lore.kernel.org/lkml/20200808023141.14227-12-changbin.du@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf ftrace: Add support for trace option funcgraph-irqs

This adds an option '--graph-opts noirqs' to filter out functions executed
in irq context.

Signed-off-by: Changbin Du <changbin.du@gmail.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: http://lore.kernel.org/lkml/20200808023141.14227-11-changbin.du@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf ftrace: Add support for trace option sleep-time

This adds an option '--graph-opts nosleep-time' which allow us only to
measure on-CPU time. This option is function_graph tracer only.

Signed-off-by: Changbin Du <changbin.du@gmail.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: http://lore.kernel.org/lkml/20200808023141.14227-10-changbin.du@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf ftrace: Add support for tracing option 'func_stack_trace'

This adds support to display call trace for function tracer. To do this,
just specify a '--func-opts call-graph' option.

Example:

$ sudo perf ftrace -T vfs_read --func-opts call-graph
iio-sensor-prox-855 [003] 6168.369657: vfs_read <-ksys_read
iio-sensor-prox-855 [003] 6168.369677: <stack trace>
=> vfs_read
=> ksys_read
=> __x64_sys_read
=> do_syscall_64
=> entry_SYSCALL_64_after_hwframe
...

Signed-off-by: Changbin Du <changbin.du@gmail.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: http://lore.kernel.org/lkml/20200808023141.14227-9-changbin.du@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf ftrace: Add option '--inherit' to trace children processes

This adds an option '--inherit' to allow us trace children
processes spawned by our target.

Signed-off-by: Changbin Du <changbin.du@gmail.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: http://lore.kernel.org/lkml/20200808023141.14227-7-changbin.du@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf ftrace: Add option '-m/--buffer-size' to set per-cpu buffer size

This adds an option '-m/--buffer-size' to allow us set the size of per-cpu
tracing buffer.

Committer testing:

Before running with this option:

# find /sys/kernel/tracing/ -name buffer_size_kb | xargs cat
1408
1408
1408
1408
1408
1408
1408
1408
1408
#

Then, run:

# perf ftrace -m 2048K | head -10
2) | mutex_unlock() {
2) ==========> |
2) | smp_irq_work_interrupt() {
2) | irq_enter() {
2) 0.121 us | rcu_irq_enter();
2) 0.128 us | irqtime_account_irq();
2) 0.719 us | }
2) | __wake_up() {
2) | __wake_up_common_lock() {
2) 0.105 us | _raw_spin_lock_irqsave();
#

Now look at those tracefs knobs:

# find /sys/kernel/tracing/ -name buffer_size_kb | xargs cat
2048
2048
2048
2048
2048
2048
2048
2048
2048
#

This should be similar to the -m option in the other perf tools, such as
'perf record', 'perf trace', etc.

Signed-off-by: Changbin Du <changbin.du@gmail.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: http://lore.kernel.org/lkml/20200808023141.14227-5-changbin.du@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf ftrace: Add option '-F/--funcs' to list available functions

This adds an option '-F/--funcs' to list all available functions to
trace, which is read from tracing file 'available_filter_functions'.

$ sudo ./perf ftrace -F | head
trace_initcall_finish_cb
initcall_blacklisted
do_one_initcall
do_one_initcall
trace_initcall_start_cb
run_init_process
try_to_run_init_process
match_dev_by_label
match_dev_by_uuid
rootfs_init_fs_context
$

Committer notes:

This is the same command line option and for the same purpose as in
'perf probe'.

Signed-off-by: Changbin Du <changbin.du@gmail.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: http://lore.kernel.org/lkml/20200808023141.14227-3-changbin.du@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf ftrace: Select function/function_graph tracer automatically

The '-g/-G' options have already implied function_graph tracer should be
used instead of function tracer. So we don't need extra option
'--tracer' in this case.

This patch changes the behavior as below:

- If '-g' or '-G' option is on, then function_graph tracer is used.
- If '-T' or '-N' option is on, then function tracer is used.
- The function_graph has priority over function tracer.
- The option '--tracer' only take effect if neither -g/-G nor -T/-N
is specified.

Here are some examples.

This will start tracing all functions using default tracer:

$ sudo perf ftrace

This will trace all functions using function graph tracer:

$ sudo perf ftrace -G '*'

This will trace function vfs_read using function graph tracer:

$ sudo perf ftrace -G vfs_read

This will trace function vfs_read using function tracer:

$ sudo perf ftrace -T vfs_read

Committer notes:

Using '-h -G' will tell what that option is about, so to further clarify
the above examples:

# perf ftrace -h -G

-G, --graph-funcs <func> Set graph filter on given functions

# perf ftrace -h -g

-g, --nograph-funcs <func> Set nograph filter on given functions

# perf ftrace -h -T

-T, --trace-funcs <func> trace given functions only

# perf ftrace -h -N

-N, --notrace-funcs <func> do not trace given functions

#

Signed-off-by: Changbin Du <changbin.du@gmail.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: http://lore.kernel.org/lkml/20200808023141.14227-2-changbin.du@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf tools: Correct title markers for asciidoctor

I've tested to process the perf man pages with asciidoctor that is
picker than asciidoc, and it revealed minor syntax errors in some
documents. Namely, the title markers aren't aligned with the previous
line, hence asciidoctor didn't recognize as titles.

This patch corrects these markers to be processed properly.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180307105441.28512-1-tiwai@suse.de
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf ftrace: Add -D option for depth filter

The -D/--graph-depth option is to set max graph depth. The following
example traces max 2-depth of page fault handler.

$ sudo perf ftrace -G __do_page_fault -D 2 -- hello
...
0) | __do_page_fault() {
0) 0.063 us | down_read_trylock();
0) 0.251 us | find_vma();
0) 5.374 us | handle_mm_fault();
0) 0.054 us | up_read();
0) 7.463 us | }
...

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: kernel-team@lge.com
Link: http://lkml.kernel.org/r/20170618142302.25390-4-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf ftrace: Add option for function filtering

The -T/--trace-funcs and -N/--notrace-funcs options are to specify
functions to enable/disable tracing dynamically.

The -G/--graph-funcs and -g/--nograph-funcs options are to set filters
for function graph tracer.

For example, to trace fault handling functions only:

$ sudo perf ftrace -T *fault hello
0) | __do_page_fault() {
0) | handle_mm_fault() {
0) 2.117 us | __handle_mm_fault();
0) 3.627 us | }
0) 7.811 us | }
0) | __do_page_fault() {
0) | handle_mm_fault() {
0) 2.014 us | __handle_mm_fault();
0) 2.424 us | }
0) 2.951 us | }
...

To trace all functions executed in __do_page_fault:

$ sudo perf ftrace -G __do_page_fault hello
2) | __do_page_fault() {
3) 0.060 us | down_read_trylock();
3) | find_vma() {
3) 0.075 us | vmacache_find();
3) 0.053 us | vmacache_update();
3) 1.246 us | }
3) | handle_mm_fault() {
3) 0.063 us | __rcu_read_lock();
3) 0.056 us | mem_cgroup_from_task();
3) 0.057 us | __rcu_read_unlock();
3) | __handle_mm_fault() {
3) | filemap_map_pages() {
3) 0.058 us | __rcu_read_lock();
3) | alloc_set_pte() {
...

But don't want to show details in handle_mm_fault:

$ sudo perf ftrace -G __do_page_fault -g handle_mm_fault hello
3) | __do_page_fault() {
3) 0.049 us | down_read_trylock();
3) | find_vma() {
3) 0.048 us | vmacache_find();
3) 0.041 us | vmacache_update();
3) 0.680 us | }
3) 0.036 us | up_read();
3) 4.547 us | } /* __do_page_fault */
...

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: kernel-team@lge.com
Link: http://lkml.kernel.org/r/20170618142302.25390-3-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf ftrace: Add support for -a and -C option

The -a/--all-cpus and -C/--cpu option is for controlling tracing cpus.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: kernel-team@lge.com
Link: http://lkml.kernel.org/r/20170224011251.14946-3-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf ftrace: Add support for --pid option

The -p (--pid) option enables to trace existing process by its pid.

Committer notes:

Testing it:

Using the function_graph tracer on a process that is just waiting for user
input and thus will make 'perf ftrace' sit there waiting for that, then press
any key on that mutt session and see what happens:

# perf ftrace -t function_graph -p `pidof mutt` | head -40
2) 1.038 us | switch_mm_irqs_off();
------------------------------------------
2) <idle>-0 => mutt-3595
------------------------------------------

2) | finish_task_switch() {
2) | smp_irq_work_interrupt() {
2) | irq_enter() {
2) 0.180 us | rcu_irq_enter();
2) 1.248 us | }
2) | __wake_up() {
2) 0.126 us | _raw_spin_lock_irqsave();
2) | __wake_up_common() {
2) | pollwake() {
2) | default_wake_function() {
2) | try_to_wake_up() {
2) 0.662 us | _raw_spin_lock_irqsave();
2) | select_task_rq_fair() {
2) 1.719 us | effective_load.isra.41();
2) 1.343 us | effective_load.isra.41();
2) | select_idle_sibling() {
2) 0.331 us | idle_cpu();
2) 1.458 us | }
2) 8.350 us | }
2) 0.200 us | _raw_spin_lock();
2) | ttwu_do_activate() {
2) | activate_task() {
2) 0.136 us | update_rq_clock.part.77();
2) | enqueue_task_fair() {
2) | enqueue_entity() {
2) 0.146 us | update_curr();
2) 0.330 us | account_entity_enqueue();
2) 0.280 us | update_cfs_shares();
2) 0.321 us | place_entity();
2) 0.206 us | __enqueue_entity();
2) 6.926 us | }
2) | enqueue_entity() {
2) 0.105 us | update_curr();
2) 0.175 us | account_entity_enqueue();
2) 0.531 us | update_cfs_shares();
#

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: kernel-team@lge.com
Link: http://lkml.kernel.org/r/20170224011251.14946-1-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf ftrace: Introduce new 'ftrace' tool

The 'perf ftrace' command is a simple wrapper of kernel's ftrace
functionality. It only supports single thread tracing currently and
just reads trace_pipe in text and then write it to stdout.

Committer notes:

Testing it:

# perf ftrace -f function_graph usleep 123456
<SNIP>
2) | SyS_nanosleep() {
2) | _copy_from_user() {
<SNIP>
2) 0.900 us | }
2) 1.354 us | }
2) | hrtimer_nanosleep() {
2) 0.062 us | __hrtimer_init();
2) | do_nanosleep() {
2) | hrtimer_start_range_ns() {
<SNIP>
2) 5.025 us | }
2) | schedule() {
2) 0.125 us | rcu_note_context_switch();
2) 0.057 us | _raw_spin_lock();
2) | deactivate_task() {
2) 0.369 us | update_rq_clock.part.77();
2) | dequeue_task_fair() {
<SNIP>
2) + 22.453 us | }
2) + 23.736 us | }
2) | pick_next_task_fair() {
<SNIP>
2) + 47.167 us | }
2) | pick_next_task_idle() {
<SNIP>
2) 4.462 us | }
------------------------------------------
2) usleep-20387 => <idle>-0
------------------------------------------

2) 0.806 us | switch_mm_irqs_off();
------------------------------------------
2) <idle>-0 => usleep-20387
------------------------------------------

2) 0.151 us | finish_task_switch();
2) @ 123597.2 us | }
2) 0.037 us | _cond_resched();
2) | hrtimer_try_to_cancel() {
2) 0.064 us | hrtimer_active();
2) 0.353 us | }
2) @ 123605.3 us | }
2) @ 123606.2 us | }
2) @ 123608.3 us | } /* SyS_nanosleep */
2) | __do_page_fault() {
<SNIP>

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jeremy Eder <jeder@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>,
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/n/tip-r1hgmsj4dxny8arn3o9mw512@git.kernel.org
[ Various foward port fixes, add man page ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>