Merge branch 'tip/perf/core' of...

- Support the TIF_SYSCALL_TRACEPOINT thread flags.

- Put the trace_sys_enter() and trace_sys_exit() tracepoints calls from ptrace

  in the ptrace syscalls tracing path.

- If the system call table on this arch is more complicated than a simple array

  of addresses of the system calls, implement an arch_syscall_addr to return

  the address of a given system call.

- If the symbol names of the system calls do not match the function names on

  this arch, define ARCH_HAS_SYSCALL_MATCH_SYM_NAME in asm/ftrace.h and

  implement arch_syscall_match_sym_name with the appropriate logic to return

  true if the function name corresponds with the symbol name.

- Tag this arch as HAVE_SYSCALL_TRACEPOINTS.

	tracers listed here can be configured by

	echoing their name into current_tracer.

  tracing_enabled:

  tracing_on:

	This sets or displays whether the current_tracer

	is activated and tracing or not. Echo 0 into this

	file to disable the tracer or 1 to enable it.

	This sets or displays whether writing to the trace

	ring buffer is enabled. Echo 0 into this file to disable

	the tracer or 1 to enable it.

  trace:

	to draw a graph of function calls similar to C code

	source.

  "sched_switch"

	Traces the context switches and wakeups between tasks.

  "irqsoff"

	Traces the areas that disable interrupts and saves

parent function that called this function "path_walk". The

timestamp is the time at which the function was entered.

The sched_switch tracer also includes tracing of task wakeups

and context switches.

     ksoftirqd/1-7     [01]  1453.070013:      7:115:R   +  2916:115:S

     ksoftirqd/1-7     [01]  1453.070013:      7:115:R   +    10:115:S

     ksoftirqd/1-7     [01]  1453.070013:      7:115:R ==>    10:115:R

        events/1-10    [01]  1453.070013:     10:115:S ==>  2916:115:R

     kondemand/1-2916  [01]  1453.070013:   2916:115:S ==>     7:115:R

     ksoftirqd/1-7     [01]  1453.070013:      7:115:S ==>     0:140:R

Wake ups are represented by a "+" and the context switches are

shown as "==>".  The format is:

 Context switches:

       Previous task              Next Task

  <pid>:<prio>:<state>  ==>  <pid>:<prio>:<state>

 Wake ups:

       Current task               Task waking up

  <pid>:<prio>:<state>    +  <pid>:<prio>:<state>

The prio is the internal kernel priority, which is the inverse

of the priority that is usually displayed by user-space tools.

Zero represents the highest priority (99). Prio 100 starts the

"nice" priorities with 100 being equal to nice -20 and 139 being

nice 19. The prio "140" is reserved for the idle task which is

the lowest priority thread (pid 0).

Latency trace format

--------------------

                   latencies, as described in "Latency

                   trace format".

sched_switch

------------

This tracer simply records schedule switches. Here is an example

of how to use it.

 # echo sched_switch > current_tracer

 # echo 1 > tracing_enabled

 # sleep 1

 # echo 0 > tracing_enabled

 # cat trace

# tracer: sched_switch

#

#           TASK-PID   CPU#    TIMESTAMP  FUNCTION

#              | |      |          |         |

            bash-3997  [01]   240.132281:   3997:120:R   +  4055:120:R

            bash-3997  [01]   240.132284:   3997:120:R ==>  4055:120:R

           sleep-4055  [01]   240.132371:   4055:120:S ==>  3997:120:R

            bash-3997  [01]   240.132454:   3997:120:R   +  4055:120:S

            bash-3997  [01]   240.132457:   3997:120:R ==>  4055:120:R

           sleep-4055  [01]   240.132460:   4055:120:D ==>  3997:120:R

            bash-3997  [01]   240.132463:   3997:120:R   +  4055:120:D

            bash-3997  [01]   240.132465:   3997:120:R ==>  4055:120:R

          <idle>-0     [00]   240.132589:      0:140:R   +     4:115:S

          <idle>-0     [00]   240.132591:      0:140:R ==>     4:115:R

     ksoftirqd/0-4     [00]   240.132595:      4:115:S ==>     0:140:R

          <idle>-0     [00]   240.132598:      0:140:R   +     4:115:S

          <idle>-0     [00]   240.132599:      0:140:R ==>     4:115:R

     ksoftirqd/0-4     [00]   240.132603:      4:115:S ==>     0:140:R

           sleep-4055  [01]   240.133058:   4055:120:S ==>  3997:120:R

 [...]

As we have discussed previously about this format, the header

shows the name of the trace and points to the options. The

"FUNCTION" is a misnomer since here it represents the wake ups

and context switches.

The sched_switch file only lists the wake ups (represented with

'+') and context switches ('==>') with the previous task or

current task first followed by the next task or task waking up.

The format for both of these is PID:KERNEL-PRIO:TASK-STATE.

Remember that the KERNEL-PRIO is the inverse of the actual

priority with zero (0) being the highest priority and the nice

values starting at 100 (nice -20). Below is a quick chart to map

the kernel priority to user land priorities.

   Kernel Space                     User Space

 ===============================================================

   0(high) to  98(low)     user RT priority 99(high) to 1(low)

                           with SCHED_RR or SCHED_FIFO

 ---------------------------------------------------------------

  99                       sched_priority is not used in scheduling

                           decisions(it must be specified as 0)

 ---------------------------------------------------------------

 100(high) to 139(low)     user nice -20(high) to 19(low)

 ---------------------------------------------------------------

 140                       idle task priority

 ---------------------------------------------------------------

The task states are:

 R - running : wants to run, may not actually be running

 S - sleep   : process is waiting to be woken up (handles signals)

 D - disk sleep (uninterruptible sleep) : process must be woken up

					(ignores signals)

 T - stopped : process suspended

 t - traced  : process is being traced (with something like gdb)

 Z - zombie  : process waiting to be cleaned up

 X - unknown

ftrace_enabled

--------------

 # echo irqsoff > current_tracer

 # echo latency-format > trace_options

 # echo 0 > tracing_max_latency

 # echo 1 > tracing_enabled

 # echo 1 > tracing_on

 # ls -ltr

 [...]

 # echo 0 > tracing_enabled

 # echo 0 > tracing_on

 # cat trace

# tracer: irqsoff

#

 # echo preemptoff > current_tracer

 # echo latency-format > trace_options

 # echo 0 > tracing_max_latency

 # echo 1 > tracing_enabled

 # echo 1 > tracing_on

 # ls -ltr

 [...]

 # echo 0 > tracing_enabled

 # echo 0 > tracing_on

 # cat trace

# tracer: preemptoff

#

 # echo preemptirqsoff > current_tracer

 # echo latency-format > trace_options

 # echo 0 > tracing_max_latency

 # echo 1 > tracing_enabled

 # echo 1 > tracing_on

 # ls -ltr

 [...]

 # echo 0 > tracing_enabled

 # echo 0 > tracing_on

 # cat trace

# tracer: preemptirqsoff

#

 # echo wakeup > current_tracer

 # echo latency-format > trace_options

 # echo 0 > tracing_max_latency

 # echo 1 > tracing_enabled

 # echo 1 > tracing_on

 # chrt -f 5 sleep 1

 # echo 0 > tracing_enabled

 # echo 0 > tracing_on

 # cat trace

# tracer: wakeup

#

 # sysctl kernel.ftrace_enabled=1

 # echo function > current_tracer

 # echo 1 > tracing_enabled

 # echo 1 > tracing_on

 # usleep 1

 # echo 0 > tracing_enabled

 # echo 0 > tracing_on

 # cat trace

# tracer: function

#

[...]

int main(int argc, char *argv[]) {

	[...]

	trace_fd = open(tracing_file("tracing_enabled"), O_WRONLY);

	trace_fd = open(tracing_file("tracing_on"), O_WRONLY);

	[...]

	if (condition_hit()) {

		write(trace_fd, "0", 1);

 # echo sys_nanosleep hrtimer_interrupt \

		> set_ftrace_filter

 # echo function > current_tracer

 # echo 1 > tracing_enabled

 # echo 1 > tracing_on

 # usleep 1

 # echo 0 > tracing_enabled

 # echo 0 > tracing_on

 # cat trace

# tracer: ftrace

#

 # echo function > current_tracer

 # cat trace_pipe > /tmp/trace.out &

[1] 4153

 # echo 1 > tracing_enabled

 # echo 1 > tracing_on

 # usleep 1

 # echo 0 > tracing_enabled

 # echo 0 > tracing_on

 # cat trace

# tracer: function

#

		.class			= &event_class_syscall_enter,	\

		.event.funcs            = &enter_syscall_print_funcs,	\

		.data			= (void *)&__syscall_meta_##sname,\

		.flags			= TRACE_EVENT_FL_CAP_ANY,	\

	};								\

	static struct ftrace_event_call __used				\

	  __attribute__((section("_ftrace_events")))			\

	 *__event_enter_##sname = &event_enter_##sname;			\

	__TRACE_EVENT_FLAGS(enter_##sname, TRACE_EVENT_FL_CAP_ANY)

	 *__event_enter_##sname = &event_enter_##sname;

#define SYSCALL_TRACE_EXIT_EVENT(sname)					\

	static struct syscall_metadata __syscall_meta_##sname;		\

		.class			= &event_class_syscall_exit,	\

		.event.funcs		= &exit_syscall_print_funcs,	\

		.data			= (void *)&__syscall_meta_##sname,\

		.flags			= TRACE_EVENT_FL_CAP_ANY,	\

	};								\

	static struct ftrace_event_call __used				\

	  __attribute__((section("_ftrace_events")))			\

	*__event_exit_##sname = &event_exit_##sname;			\

	__TRACE_EVENT_FLAGS(exit_##sname, TRACE_EVENT_FL_CAP_ANY)

	*__event_exit_##sname = &event_exit_##sname;

#define SYSCALL_METADATA(sname, nb)				\

	SYSCALL_TRACE_ENTER_EVENT(sname);			\

	static struct syscall_metadata __used			\

	  __syscall_meta_##sname = {				\

		.name 		= "sys"#sname,			\

		.syscall_nr	= -1,	/* Filled in at boot */	\

		.nb_args 	= nb,				\

		.types		= types_##sname,		\

		.args		= args_##sname,			\

	static struct syscall_metadata __used			\

	  __syscall_meta__##sname = {				\

		.name 		= "sys_"#sname,			\

		.syscall_nr	= -1,	/* Filled in at boot */	\

		.nb_args 	= 0,				\

		.enter_event	= &event_enter__##sname,	\

		.exit_event	= &event_exit__##sname,		\

		delta = diff;

		if (unlikely(test_time_stamp(delta))) {

			WARN_ONCE(delta > (1ULL << 59),

				  KERN_WARNING "Delta way too big! %llu ts=%llu write stamp = %llu\n",

				  KERN_WARNING "Delta way too big! %llu ts=%llu write stamp = %llu\n%s",

				  (unsigned long long)delta,

				  (unsigned long long)ts,

				  (unsigned long long)cpu_buffer->write_stamp);

				  (unsigned long long)cpu_buffer->write_stamp,

				  sched_clock_stable ? "" :

				  "If you just came from a suspend/resume,\n"

				  "please switch to the trace global clock:\n"

				  "  echo global > /sys/kernel/debug/tracing/trace_clock\n");

			add_timestamp = 1;

		}

	}

	mutex_lock(&trace_types_lock);

	if (tracer_enabled ^ val) {

		/* Only need to warn if this is used to change the state */

		WARN_ONCE(1, "tracing_enabled is deprecated. Use tracing_on");

		if (val) {

			tracer_enabled = 1;

			if (current_trace->start)