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Commit 49ff5903 authored by Steven Rostedt's avatar Steven Rostedt Committed by Steven Rostedt
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tracing: add latency format to function_graph tracer 



While debugging something with the function_graph tracer, I found the
need to see the preempt count of the traces. Unfortunately, since
the function graph tracer has its own output formatting, it does not
honor the latency-format option.

This patch makes the function_graph tracer honor the latency-format
option, but still keeps control of the output. But now we have the
same details that the latency-format supplies.

 # tracer: function_graph
 #
 #      _-----=> irqs-off
 #     / _----=> need-resched
 #    | / _---=> hardirq/softirq
 #    || / _--=> preempt-depth
 #    ||| /
 #    ||||
 # CPU||||  DURATION                  FUNCTION CALLS
 # |  ||||   |   |                     |   |   |   |
  3)  d..1  1.333 us    |        idle_cpu();
  3)  d.h1              |        tick_check_idle() {
  3)  d.h1  0.550 us    |          tick_check_oneshot_broadcast();
  3)  d.h1              |          tick_nohz_stop_idle() {
  3)  d.h1              |            ktime_get() {
  3)  d.h1              |              ktime_get_ts() {

Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent fc06b852

kernel/trace/trace_functions_graph.c

+68 −6
Original line number Diff line number Diff line
@@ -364,6 +364,29 @@ print_graph_proc(struct trace_seq *s, pid_t pid) 
}





static enum print_line_t

print_graph_lat_fmt(struct trace_seq *s, struct trace_entry *entry)

{

	int hardirq, softirq;



	hardirq = entry->flags & TRACE_FLAG_HARDIRQ;

	softirq = entry->flags & TRACE_FLAG_SOFTIRQ;



	if (!trace_seq_printf(s, " %c%c%c",

			      (entry->flags & TRACE_FLAG_IRQS_OFF) ? 'd' :

				(entry->flags & TRACE_FLAG_IRQS_NOSUPPORT) ?

				  'X' : '.',

			      (entry->flags & TRACE_FLAG_NEED_RESCHED) ?

				'N' : '.',

			      (hardirq && softirq) ? 'H' :

				hardirq ? 'h' : softirq ? 's' : '.'))

		return 0;



	if (entry->preempt_count)

		return trace_seq_printf(s, "%x", entry->preempt_count);

	return trace_seq_puts(s, ".");

}



/* If the pid changed since the last trace, output this event */

static enum print_line_t

verif_pid(struct trace_seq *s, pid_t pid, int cpu, struct fgraph_data *data)
@@ -521,6 +544,7 @@ print_graph_irq(struct trace_iterator *iter, unsigned long addr, 
		if (ret == TRACE_TYPE_PARTIAL_LINE)

			return TRACE_TYPE_PARTIAL_LINE;

	}



	/* Proc */

	if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC) {

		ret = print_graph_proc(s, pid);
@@ -758,6 +782,13 @@ print_graph_prologue(struct trace_iterator *iter, struct trace_seq *s, 
			return TRACE_TYPE_PARTIAL_LINE;

	}



	/* Latency format */

	if (trace_flags & TRACE_ITER_LATENCY_FMT) {

		ret = print_graph_lat_fmt(s, ent);

		if (ret == TRACE_TYPE_PARTIAL_LINE)

			return TRACE_TYPE_PARTIAL_LINE;

	}



	return 0;

}
@@ -952,8 +983,35 @@ print_graph_function(struct trace_iterator *iter) 
	return TRACE_TYPE_HANDLED;

}



static void print_lat_header(struct seq_file *s)

{

	static const char spaces[] = "                "	/* 16 spaces */

		"    "					/* 4 spaces */

		"                 ";			/* 17 spaces */

	int size = 0;



	if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME)

		size += 16;

	if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU)

		size += 4;

	if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC)

		size += 17;



	seq_printf(s, "#%.*s  _-----=> irqs-off        \n", size, spaces);

	seq_printf(s, "#%.*s / _----=> need-resched    \n", size, spaces);

	seq_printf(s, "#%.*s| / _---=> hardirq/softirq \n", size, spaces);

	seq_printf(s, "#%.*s|| / _--=> preempt-depth   \n", size, spaces);

	seq_printf(s, "#%.*s||| /                      \n", size, spaces);

	seq_printf(s, "#%.*s||||                       \n", size, spaces);

}



static void print_graph_headers(struct seq_file *s)

{

	int lat = trace_flags & TRACE_ITER_LATENCY_FMT;



	if (lat)

		print_lat_header(s);



	/* 1st line */

	seq_printf(s, "#");

	if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME)
@@ -962,6 +1020,8 @@ static void print_graph_headers(struct seq_file *s) 
		seq_printf(s, " CPU");

	if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC)

		seq_printf(s, "  TASK/PID       ");

	if (lat)

		seq_printf(s, "||||");

	if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION)

		seq_printf(s, "  DURATION   ");

	seq_printf(s, "               FUNCTION CALLS\n");
@@ -974,6 +1034,8 @@ static void print_graph_headers(struct seq_file *s) 
		seq_printf(s, " |  ");

	if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC)

		seq_printf(s, "   |    |        ");

	if (lat)

		seq_printf(s, "||||");

	if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION)

		seq_printf(s, "   |   |      ");

	seq_printf(s, "               |   |   |   |\n");