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Commit 83a8df61 authored by Frederic Weisbecker's avatar Frederic Weisbecker Committed by Ingo Molnar
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tracing/function-graph-tracer: enhancements for the trace output 



Impact: enhance the output of the graph-tracer

This patch applies some ideas of Ingo Molnar and Steven Rostedt.

* Output leaf functions in one line with parenthesis, semicolon and duration
  output.

* Add a second column (after cpu) for an overhead sign.
  if duration > 100 us, "!"
  if duration > 10 us, "+"
  else " "

* Print output in us with remaining nanosec: u.n

* Print duration on the right end, following the indentation of the functions.
  Use also visual clues: "-" on entry call (no duration to output) and "+" on
  return (duration output).

The name of the tracer has been fixed as well: function-branch becomes
function_branch.

Here is an example of the new output:

CPU[000]           dequeue_entity() {                    -
CPU[000]             update_curr() {                    -
CPU[000]               update_min_vruntime();                    + 0.512 us
CPU[000]             }                                + 1.504 us
CPU[000]             clear_buddies();                    + 0.481 us
CPU[000]             update_min_vruntime();                    + 0.504 us
CPU[000]           }                                + 4.557 us
CPU[000]           hrtick_update() {                    -
CPU[000]             hrtick_start_fair();                    + 0.489 us
CPU[000]           }                                + 1.443 us
CPU[000] +       }                                + 14.655 us
CPU[000] +     }                                + 15.678 us
CPU[000] +   }                                + 16.686 us
CPU[000]     msecs_to_jiffies();                    + 0.481 us
CPU[000]     put_prev_task_fair();                    + 0.504 us
CPU[000]     pick_next_task_fair();                    + 0.482 us
CPU[000]     pick_next_task_rt();                    + 0.504 us
CPU[000]     pick_next_task_fair();                    + 0.481 us
CPU[000]     pick_next_task_idle();                    + 0.489 us
CPU[000]     _spin_trylock();                    + 0.655 us
CPU[000]     _spin_unlock();                    + 0.609 us

CPU[000]  ------------8<---------- thread bash-2794 ------------8<----------

CPU[000]               finish_task_switch() {                    -
CPU[000]                 _spin_unlock_irq();                    + 0.722 us
CPU[000]               }                                + 2.369 us
CPU[000] !           }                                + 501972.605 us
CPU[000] !         }                                + 501973.763 us
CPU[000]           copy_from_read_buf() {                    -
CPU[000]             _spin_lock_irqsave();                    + 0.670 us
CPU[000]             _spin_unlock_irqrestore();                    + 0.699 us
CPU[000]             copy_to_user() {                    -
CPU[000]               might_fault() {                    -
CPU[000]                 __might_sleep();                    + 0.503 us
CPU[000]               }                                + 1.632 us
CPU[000]               __copy_to_user_ll();                    + 0.542 us
CPU[000]             }                                + 3.858 us
CPU[000]             tty_audit_add_data() {                    -
CPU[000]               _spin_lock_irq();                    + 0.609 us
CPU[000]               _spin_unlock_irq();                    + 0.624 us
CPU[000]             }                                + 3.196 us
CPU[000]             _spin_lock_irqsave();                    + 0.624 us
CPU[000]             _spin_unlock_irqrestore();                    + 0.625 us
CPU[000] +         }                                + 13.611 us
CPU[000]           copy_from_read_buf() {                    -
CPU[000]             _spin_lock_irqsave();                    + 0.624 us
CPU[000]             _spin_unlock_irqrestore();                    + 0.616 us
CPU[000]           }                                + 2.820 us
CPU[000]

Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent c7cc7730

kernel/trace/trace_functions_graph.c

+159 −9
Original line number Original line Diff line number Diff line
@@ -14,6 +14,10 @@ 
#include "trace.h"

#include "trace.h"





#define TRACE_GRAPH_INDENT	2

#define TRACE_GRAPH_INDENT	2

/* Spaces between function call and time duration */

#define TRACE_GRAPH_TIMESPACE_ENTRY	"                    "

/* Spaces between function call and closing braces */

#define TRACE_GRAPH_TIMESPACE_RET	"                               "





#define TRACE_GRAPH_PRINT_OVERRUN	0x1

#define TRACE_GRAPH_PRINT_OVERRUN	0x1

static struct tracer_opt trace_opts[] = {

static struct tracer_opt trace_opts[] = {
@@ -69,20 +73,124 @@ static int verif_pid(struct trace_seq *s, pid_t pid, int cpu) 
				    cpu, comm, pid);

				    cpu, comm, pid);

}

}





static bool

trace_branch_is_leaf(struct trace_iterator *iter,

		struct ftrace_graph_ent_entry *curr)

{

	struct ring_buffer_iter *ring_iter;

	struct ring_buffer_event *event;

	struct ftrace_graph_ret_entry *next;



	ring_iter = iter->buffer_iter[iter->cpu];



	if (!ring_iter)

		return false;



	event = ring_buffer_iter_peek(iter->buffer_iter[iter->cpu], NULL);



	if (!event)

		return false;



	next = ring_buffer_event_data(event);



	if (next->ent.type != TRACE_GRAPH_RET)

		return false;



	if (curr->ent.pid != next->ent.pid ||

			curr->graph_ent.func != next->ret.func)

		return false;



	return true;

}





static inline int

print_graph_duration(unsigned long long duration, struct trace_seq *s)

{

	unsigned long nsecs_rem = do_div(duration, 1000);

	return trace_seq_printf(s, "+ %llu.%lu us\n", duration, nsecs_rem);

}



/* Signal a overhead of time execution to the output */

static int

print_graph_overhead(unsigned long long duration, struct trace_seq *s)

{

	/* Duration exceeded 100 msecs */

	if (duration > 100000ULL)

		return trace_seq_printf(s, "! ");



	/* Duration exceeded 10 msecs */

	if (duration > 10000ULL)

		return trace_seq_printf(s, "+ ");



	return trace_seq_printf(s, "  ");

}



/* Case of a leaf function on its call entry */

static enum print_line_t

static enum print_line_t

print_graph_entry(struct ftrace_graph_ent *call, struct trace_seq *s,

print_graph_entry_leaf(struct trace_iterator *iter,

		  struct trace_entry *ent, int cpu)

		struct ftrace_graph_ent_entry *entry, struct trace_seq *s)

{

{

	struct ftrace_graph_ret_entry *ret_entry;

	struct ftrace_graph_ret *graph_ret;

	struct ring_buffer_event *event;

	struct ftrace_graph_ent *call;

	unsigned long long duration;

	int i;

	int i;

	int ret;

	int ret;





	if (!verif_pid(s, ent->pid, cpu))

	event = ring_buffer_read(iter->buffer_iter[iter->cpu], NULL);

	ret_entry = ring_buffer_event_data(event);

	graph_ret = &ret_entry->ret;

	call = &entry->graph_ent;

	duration = graph_ret->rettime - graph_ret->calltime;



	/* Overhead */

	ret = print_graph_overhead(duration, s);

	if (!ret)

		return TRACE_TYPE_PARTIAL_LINE;

		return TRACE_TYPE_PARTIAL_LINE;





	ret = trace_seq_printf(s, "CPU[%03d] ", cpu);

	/* Function */

	for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {

		ret = trace_seq_printf(s, " ");

		if (!ret)

		if (!ret)

			return TRACE_TYPE_PARTIAL_LINE;

			return TRACE_TYPE_PARTIAL_LINE;

	}





	ret = seq_print_ip_sym(s, call->func, 0);

	if (!ret)

		return TRACE_TYPE_PARTIAL_LINE;



	ret = trace_seq_printf(s, "();");

	if (!ret)

		return TRACE_TYPE_PARTIAL_LINE;



	/* Duration */

	ret = trace_seq_printf(s, TRACE_GRAPH_TIMESPACE_ENTRY);

	if (!ret)

		return TRACE_TYPE_PARTIAL_LINE;



	ret = print_graph_duration(duration, s);

	if (!ret)

		return TRACE_TYPE_PARTIAL_LINE;



	return TRACE_TYPE_HANDLED;

}



static enum print_line_t

print_graph_entry_nested(struct ftrace_graph_ent_entry *entry,

			struct trace_seq *s)

{

	int i;

	int ret;

	struct ftrace_graph_ent *call = &entry->graph_ent;



	/* No overhead */

	ret = trace_seq_printf(s, "  ");

	if (!ret)

		return TRACE_TYPE_PARTIAL_LINE;



	/* Function */

	for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {

	for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {

		ret = trace_seq_printf(s, " ");

		ret = trace_seq_printf(s, " ");

		if (!ret)

		if (!ret)
@@ -93,26 +201,62 @@ print_graph_entry(struct ftrace_graph_ent *call, struct trace_seq *s, 
	if (!ret)

	if (!ret)

		return TRACE_TYPE_PARTIAL_LINE;

		return TRACE_TYPE_PARTIAL_LINE;





	ret = trace_seq_printf(s, "() {\n");

	ret = trace_seq_printf(s, "() {");

	if (!ret)

	if (!ret)

		return TRACE_TYPE_PARTIAL_LINE;

		return TRACE_TYPE_PARTIAL_LINE;



	/* No duration to print at this state */

	ret = trace_seq_printf(s, TRACE_GRAPH_TIMESPACE_ENTRY "-\n");

	if (!ret)

		return TRACE_TYPE_PARTIAL_LINE;



	return TRACE_TYPE_HANDLED;

	return TRACE_TYPE_HANDLED;

}

}





static enum print_line_t

print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,

			struct trace_iterator *iter, int cpu)

{

	int ret;

	struct trace_entry *ent = iter->ent;



	if (!verif_pid(s, ent->pid, cpu))

		return TRACE_TYPE_PARTIAL_LINE;



	ret = trace_seq_printf(s, "CPU[%03d] ", cpu);

	if (!ret)

		return TRACE_TYPE_PARTIAL_LINE;



	if (trace_branch_is_leaf(iter, field))

		return print_graph_entry_leaf(iter, field, s);

	else

		return print_graph_entry_nested(field, s);



}



static enum print_line_t

static enum print_line_t

print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,

print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,

		   struct trace_entry *ent, int cpu)

		   struct trace_entry *ent, int cpu)

{

{

	int i;

	int i;

	int ret;

	int ret;

	unsigned long long duration = trace->rettime - trace->calltime;





	/* Pid */

	if (!verif_pid(s, ent->pid, cpu))

	if (!verif_pid(s, ent->pid, cpu))

		return TRACE_TYPE_PARTIAL_LINE;

		return TRACE_TYPE_PARTIAL_LINE;





	/* Cpu */

	ret = trace_seq_printf(s, "CPU[%03d] ", cpu);

	ret = trace_seq_printf(s, "CPU[%03d] ", cpu);

	if (!ret)

	if (!ret)

		return TRACE_TYPE_PARTIAL_LINE;

		return TRACE_TYPE_PARTIAL_LINE;





	/* Overhead */

	ret = print_graph_overhead(duration, s);

	if (!ret)

		return TRACE_TYPE_PARTIAL_LINE;



	/* Closing brace */

	for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++) {

	for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++) {

		ret = trace_seq_printf(s, " ");

		ret = trace_seq_printf(s, " ");

		if (!ret)

		if (!ret)
@@ -123,10 +267,16 @@ print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s, 
	if (!ret)

	if (!ret)

		return TRACE_TYPE_PARTIAL_LINE;

		return TRACE_TYPE_PARTIAL_LINE;





	ret = trace_seq_printf(s, "%llu\n", trace->rettime - trace->calltime);

	/* Duration */

	ret = trace_seq_printf(s, TRACE_GRAPH_TIMESPACE_RET);

	if (!ret)

		return TRACE_TYPE_PARTIAL_LINE;



	ret = print_graph_duration(duration, s);

	if (!ret)

	if (!ret)

		return TRACE_TYPE_PARTIAL_LINE;

		return TRACE_TYPE_PARTIAL_LINE;





	/* Overrun */

	if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERRUN) {

	if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERRUN) {

		ret = trace_seq_printf(s, " (Overruns: %lu)\n",

		ret = trace_seq_printf(s, " (Overruns: %lu)\n",

					trace->overrun);

					trace->overrun);
@@ -146,7 +296,7 @@ print_graph_function(struct trace_iterator *iter) 
	case TRACE_GRAPH_ENT: {

	case TRACE_GRAPH_ENT: {

		struct ftrace_graph_ent_entry *field;

		struct ftrace_graph_ent_entry *field;

		trace_assign_type(field, entry);

		trace_assign_type(field, entry);

		return print_graph_entry(&field->graph_ent, s, entry,

		return print_graph_entry(field, s, iter,

					 iter->cpu);

					 iter->cpu);

	}

	}

	case TRACE_GRAPH_RET: {

	case TRACE_GRAPH_RET: {
@@ -160,7 +310,7 @@ print_graph_function(struct trace_iterator *iter) 
}

}





static struct tracer graph_trace __read_mostly = {

static struct tracer graph_trace __read_mostly = {

	.name	     = "function-graph",

	.name	     = "function_graph",

	.init	     = graph_trace_init,

	.init	     = graph_trace_init,

	.reset	     = graph_trace_reset,

	.reset	     = graph_trace_reset,

	.print_line = print_graph_function,

	.print_line = print_graph_function,