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Commit d1f9cbd7 authored by Frederic Weisbecker's avatar Frederic Weisbecker Committed by Ingo Molnar
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tracing/function-graph-tracer: fix traces weirdness while absolute time printing 



Impact: trace output cleanup/reordering

When an interrupt occurs and and the abstime option is selected:

  echo funcgraph-abstime > /debug/tracing/trace_options

then we observe broken traces:

30581.025422 |   0)   Xorg-4291    |   0.503 us    |      idle_cpu();
30581.025424 |   0)   Xorg-4291    |   2.576 us    |    }
30581.025424 |   0)   Xorg-4291    | + 75.771 us   |  }
 0)   Xorg-4291    |   <========== |
30581.025425 |   0)   Xorg-4291    |               |  schedule() {
30581.025426 |   0)   Xorg-4291    |               |    __schedule() {
30581.025426 |   0)   Xorg-4291    |   0.705 us    |      _spin_lock_irq();

With this patch, the interrupts output better adapts
to absolute time printing:

  414.856543 |   1)   Xorg-4279    |   8.816 us    |                        }
  414.856544 |   1)   Xorg-4279    |   0.525 us    |                        rcu_irq_exit();
  414.856545 |   1)   Xorg-4279    |   0.526 us    |                        idle_cpu();
  414.856546 |   1)   Xorg-4279    | + 12.157 us   |                      }
  414.856549 |   1)   Xorg-4279    | ! 104.114 us  |                    }
  414.856549 |   1)   Xorg-4279    |   <========== |
  414.856549 |   1)   Xorg-4279    | ! 107.944 us  |                  }
  414.856550 |   1)   Xorg-4279    | ! 137.010 us  |                }
  414.856551 |   1)   Xorg-4279    |   0.624 us    |                _read_unlock();
  414.856552 |   1)   Xorg-4279    | ! 140.930 us  |              }
  414.856552 |   1)   Xorg-4279    | ! 166.159 us  |            }

Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 4cd0332d

kernel/trace/trace_functions_graph.c

+29 −21
Original line number Diff line number Diff line
@@ -351,16 +351,35 @@ print_graph_overhead(unsigned long long duration, struct trace_seq *s) 
	return trace_seq_printf(s, "  ");

}



static int print_graph_abs_time(u64 t, struct trace_seq *s)

{

	unsigned long usecs_rem;



	usecs_rem = do_div(t, NSEC_PER_SEC);

	usecs_rem /= 1000;



	return trace_seq_printf(s, "%5lu.%06lu |  ",

			(unsigned long)t, usecs_rem);

}



static enum print_line_t

print_graph_irq(struct trace_seq *s, unsigned long addr,

print_graph_irq(struct trace_iterator *iter, unsigned long addr,

		enum trace_type type, int cpu, pid_t pid)

{

	int ret;

	struct trace_seq *s = &iter->seq;



	if (addr < (unsigned long)__irqentry_text_start ||

		addr >= (unsigned long)__irqentry_text_end)

		return TRACE_TYPE_UNHANDLED;



	/* Absolute time */

	if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME) {

		ret = print_graph_abs_time(iter->ts, s);

		if (!ret)

			return TRACE_TYPE_PARTIAL_LINE;

	}



	/* Cpu */

	if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) {

		ret = print_graph_cpu(s, cpu);
@@ -446,17 +465,6 @@ print_graph_duration(unsigned long long duration, struct trace_seq *s) 


}



static int print_graph_abs_time(u64 t, struct trace_seq *s)

{

	unsigned long usecs_rem;



	usecs_rem = do_div(t, 1000000000);

	usecs_rem /= 1000;



	return trace_seq_printf(s, "%5lu.%06lu |  ",

			(unsigned long)t, usecs_rem);

}



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

static enum print_line_t

print_graph_entry_leaf(struct trace_iterator *iter,
@@ -561,7 +569,7 @@ print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s, 
		return TRACE_TYPE_PARTIAL_LINE;



	/* Interrupt */

	ret = print_graph_irq(s, call->func, TRACE_GRAPH_ENT, cpu, ent->pid);

	ret = print_graph_irq(iter, call->func, TRACE_GRAPH_ENT, cpu, ent->pid);

	if (ret == TRACE_TYPE_PARTIAL_LINE)

		return TRACE_TYPE_PARTIAL_LINE;
@@ -581,7 +589,7 @@ print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s, 


	/* Proc */

	if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC) {

		ret = print_graph_proc(s, ent->pid);

		ret = print_graph_proc(s, pid);

		if (ret == TRACE_TYPE_PARTIAL_LINE)

			return TRACE_TYPE_PARTIAL_LINE;
@@ -605,11 +613,11 @@ print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s, 
	int i;

	int ret;

	int cpu = iter->cpu;

	pid_t *last_pid = iter->private;

	pid_t *last_pid = iter->private, pid = ent->pid;

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



	/* Pid */

	if (verif_pid(s, ent->pid, cpu, last_pid) == TRACE_TYPE_PARTIAL_LINE)

	if (verif_pid(s, pid, cpu, last_pid) == TRACE_TYPE_PARTIAL_LINE)

		return TRACE_TYPE_PARTIAL_LINE;



	/* Absolute time */
@@ -668,7 +676,7 @@ print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s, 
			return TRACE_TYPE_PARTIAL_LINE;

	}



	ret = print_graph_irq(s, trace->func, TRACE_GRAPH_RET, cpu, ent->pid);

	ret = print_graph_irq(iter, trace->func, TRACE_GRAPH_RET, cpu, pid);

	if (ret == TRACE_TYPE_PARTIAL_LINE)

		return TRACE_TYPE_PARTIAL_LINE;
@@ -684,6 +692,10 @@ print_graph_comment(struct print_entry *trace, struct trace_seq *s, 
	int cpu = iter->cpu;

	pid_t *last_pid = iter->private;



	/* Pid */

	if (verif_pid(s, ent->pid, cpu, last_pid) == TRACE_TYPE_PARTIAL_LINE)

		return TRACE_TYPE_PARTIAL_LINE;



	/* Absolute time */

	if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME) {

		ret = print_graph_abs_time(iter->ts, s);
@@ -691,10 +703,6 @@ print_graph_comment(struct print_entry *trace, struct trace_seq *s, 
			return TRACE_TYPE_PARTIAL_LINE;

	}



	/* Pid */

	if (verif_pid(s, ent->pid, cpu, last_pid) == TRACE_TYPE_PARTIAL_LINE)

		return TRACE_TYPE_PARTIAL_LINE;



	/* Cpu */

	if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) {

		ret = print_graph_cpu(s, cpu);