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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
Show whitespace changes
Inline Side-by-side
Showing with 159 additions and 9 deletions
kernel/trace/trace_functions_graph.c
View file @ 83a8df61
......@@ -14,6 +14,10 @@
#include "trace.h"
#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
static struct tracer_opt trace_opts[] = {
......@@ -63,26 +67,130 @@ static int verif_pid(struct trace_seq *s, pid_t pid, int cpu)
last_pid[cpu] = pid;
comm = trace_find_cmdline(pid);
return trace_seq_printf(s, "\nCPU[%03d]"
return trace_seq_printf(s, "\nCPU[%03d] "
" ------------8<---------- thread %s-%d"
" ------------8<----------\n\n",
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
print_graph_entry(struct ftrace_graph_ent *call, struct trace_seq *s,
struct trace_entry *ent, int cpu)
print_graph_entry_leaf(struct trace_iterator *iter,
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 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;
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)
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++) {
ret = trace_seq_printf(s, " ");
if (!ret)
......@@ -93,26 +201,62 @@ print_graph_entry(struct ftrace_graph_ent *call, struct trace_seq *s,
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
ret = trace_seq_printf(s, "() {\n");
ret = trace_seq_printf(s, "() {");
if (!ret)
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;
}
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
print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
struct trace_entry *ent, int cpu)
{
int i;
int ret;
unsigned long long duration = trace->rettime - trace->calltime;
/* Pid */
if (!verif_pid(s, ent->pid, cpu))
return TRACE_TYPE_PARTIAL_LINE;
/* Cpu */
ret = trace_seq_printf(s, "CPU[%03d] ", cpu);
if (!ret)
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++) {
ret = trace_seq_printf(s, " ");
if (!ret)
......@@ -123,10 +267,16 @@ print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
if (!ret)
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)
return TRACE_TYPE_PARTIAL_LINE;
/* Overrun */
if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERRUN) {
ret = trace_seq_printf(s, " (Overruns: %lu)\n",
trace->overrun);
......@@ -146,7 +296,7 @@ print_graph_function(struct trace_iterator *iter)
case TRACE_GRAPH_ENT: {
struct ftrace_graph_ent_entry *field;
trace_assign_type(field, entry);
return print_graph_entry(&field->graph_ent, s, entry,
return print_graph_entry(field, s, iter,
iter->cpu);
}
case TRACE_GRAPH_RET: {
......@@ -160,7 +310,7 @@ print_graph_function(struct trace_iterator *iter)
}
static struct tracer graph_trace __read_mostly = {
.name = "function-graph",
.name = "function_graph",
.init = graph_trace_init,
.reset = graph_trace_reset,
.print_line = print_graph_function,
......
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