tracing: Add graph output support for irqsoff tracer
Add function graph output to irqsoff tracer.
The graph output is enabled by setting new 'display-graph' trace option.
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
LKML-Reference: <1270227683-14631-4-git-send-email-jolsa@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
index 2974bc7..6fd486e 100644
--- a/kernel/trace/trace_irqsoff.c
+++ b/kernel/trace/trace_irqsoff.c
@@ -34,6 +34,9 @@
static int save_lat_flag;
+static void stop_irqsoff_tracer(struct trace_array *tr, int graph);
+static int start_irqsoff_tracer(struct trace_array *tr, int graph);
+
#ifdef CONFIG_PREEMPT_TRACER
static inline int
preempt_trace(void)
@@ -55,6 +58,23 @@
# define irq_trace() (0)
#endif
+#define TRACE_DISPLAY_GRAPH 1
+
+static struct tracer_opt trace_opts[] = {
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+ /* display latency trace as call graph */
+ { TRACER_OPT(display-graph, TRACE_DISPLAY_GRAPH) },
+#endif
+ { } /* Empty entry */
+};
+
+static struct tracer_flags tracer_flags = {
+ .val = 0,
+ .opts = trace_opts,
+};
+
+#define is_graph() (tracer_flags.val & TRACE_DISPLAY_GRAPH)
+
/*
* Sequence count - we record it when starting a measurement and
* skip the latency if the sequence has changed - some other section
@@ -108,6 +128,202 @@
};
#endif /* CONFIG_FUNCTION_TRACER */
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+static int irqsoff_set_flag(u32 old_flags, u32 bit, int set)
+{
+ int cpu;
+
+ if (!(bit & TRACE_DISPLAY_GRAPH))
+ return -EINVAL;
+
+ if (!(is_graph() ^ set))
+ return 0;
+
+ stop_irqsoff_tracer(irqsoff_trace, !set);
+
+ for_each_possible_cpu(cpu)
+ per_cpu(tracing_cpu, cpu) = 0;
+
+ tracing_max_latency = 0;
+ tracing_reset_online_cpus(irqsoff_trace);
+
+ return start_irqsoff_tracer(irqsoff_trace, set);
+}
+
+static int irqsoff_graph_entry(struct ftrace_graph_ent *trace)
+{
+ struct trace_array *tr = irqsoff_trace;
+ struct trace_array_cpu *data;
+ unsigned long flags;
+ long disabled;
+ int ret;
+ int cpu;
+ int pc;
+
+ cpu = raw_smp_processor_id();
+ if (likely(!per_cpu(tracing_cpu, cpu)))
+ return 0;
+
+ local_save_flags(flags);
+ /* slight chance to get a false positive on tracing_cpu */
+ if (!irqs_disabled_flags(flags))
+ return 0;
+
+ data = tr->data[cpu];
+ disabled = atomic_inc_return(&data->disabled);
+
+ if (likely(disabled == 1)) {
+ pc = preempt_count();
+ ret = __trace_graph_entry(tr, trace, flags, pc);
+ } else
+ ret = 0;
+
+ atomic_dec(&data->disabled);
+ return ret;
+}
+
+static void irqsoff_graph_return(struct ftrace_graph_ret *trace)
+{
+ struct trace_array *tr = irqsoff_trace;
+ struct trace_array_cpu *data;
+ unsigned long flags;
+ long disabled;
+ int cpu;
+ int pc;
+
+ cpu = raw_smp_processor_id();
+ if (likely(!per_cpu(tracing_cpu, cpu)))
+ return;
+
+ local_save_flags(flags);
+ /* slight chance to get a false positive on tracing_cpu */
+ if (!irqs_disabled_flags(flags))
+ return;
+
+ data = tr->data[cpu];
+ disabled = atomic_inc_return(&data->disabled);
+
+ if (likely(disabled == 1)) {
+ pc = preempt_count();
+ __trace_graph_return(tr, trace, flags, pc);
+ }
+
+ atomic_dec(&data->disabled);
+}
+
+static void irqsoff_trace_open(struct trace_iterator *iter)
+{
+ if (is_graph())
+ graph_trace_open(iter);
+
+}
+
+static void irqsoff_trace_close(struct trace_iterator *iter)
+{
+ if (iter->private)
+ graph_trace_close(iter);
+}
+
+#define GRAPH_TRACER_FLAGS (TRACE_GRAPH_PRINT_CPU | \
+ TRACE_GRAPH_PRINT_PROC)
+
+static enum print_line_t irqsoff_print_line(struct trace_iterator *iter)
+{
+ u32 flags = GRAPH_TRACER_FLAGS;
+
+ if (trace_flags & TRACE_ITER_LATENCY_FMT)
+ flags |= TRACE_GRAPH_PRINT_DURATION;
+ else
+ flags |= TRACE_GRAPH_PRINT_ABS_TIME;
+
+ /*
+ * In graph mode call the graph tracer output function,
+ * otherwise go with the TRACE_FN event handler
+ */
+ if (is_graph())
+ return print_graph_function_flags(iter, flags);
+
+ return TRACE_TYPE_UNHANDLED;
+}
+
+static void irqsoff_print_header(struct seq_file *s)
+{
+ if (is_graph()) {
+ struct trace_iterator *iter = s->private;
+ u32 flags = GRAPH_TRACER_FLAGS;
+
+ if (trace_flags & TRACE_ITER_LATENCY_FMT) {
+ /* print nothing if the buffers are empty */
+ if (trace_empty(iter))
+ return;
+
+ print_trace_header(s, iter);
+ flags |= TRACE_GRAPH_PRINT_DURATION;
+ } else
+ flags |= TRACE_GRAPH_PRINT_ABS_TIME;
+
+ print_graph_headers_flags(s, flags);
+ } else
+ trace_default_header(s);
+}
+
+static void
+trace_graph_function(struct trace_array *tr,
+ unsigned long ip, unsigned long flags, int pc)
+{
+ u64 time = trace_clock_local();
+ struct ftrace_graph_ent ent = {
+ .func = ip,
+ .depth = 0,
+ };
+ struct ftrace_graph_ret ret = {
+ .func = ip,
+ .depth = 0,
+ .calltime = time,
+ .rettime = time,
+ };
+
+ __trace_graph_entry(tr, &ent, flags, pc);
+ __trace_graph_return(tr, &ret, flags, pc);
+}
+
+static void
+__trace_function(struct trace_array *tr,
+ unsigned long ip, unsigned long parent_ip,
+ unsigned long flags, int pc)
+{
+ if (!is_graph())
+ trace_function(tr, ip, parent_ip, flags, pc);
+ else {
+ trace_graph_function(tr, parent_ip, flags, pc);
+ trace_graph_function(tr, ip, flags, pc);
+ }
+}
+
+#else
+#define __trace_function trace_function
+
+static int irqsoff_set_flag(u32 old_flags, u32 bit, int set)
+{
+ return -EINVAL;
+}
+
+static int irqsoff_graph_entry(struct ftrace_graph_ent *trace)
+{
+ return -1;
+}
+
+static enum print_line_t irqsoff_print_line(struct trace_iterator *iter)
+{
+ return TRACE_TYPE_UNHANDLED;
+}
+
+static void irqsoff_graph_return(struct ftrace_graph_ret *trace) { }
+static void irqsoff_print_header(struct seq_file *s) { }
+static void irqsoff_trace_open(struct trace_iterator *iter) { }
+static void irqsoff_trace_close(struct trace_iterator *iter) { }
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
+
/*
* Should this new latency be reported/recorded?
*/
@@ -150,7 +366,7 @@
if (!report_latency(delta))
goto out_unlock;
- trace_function(tr, CALLER_ADDR0, parent_ip, flags, pc);
+ __trace_function(tr, CALLER_ADDR0, parent_ip, flags, pc);
/* Skip 5 functions to get to the irq/preempt enable function */
__trace_stack(tr, flags, 5, pc);
@@ -172,7 +388,7 @@
out:
data->critical_sequence = max_sequence;
data->preempt_timestamp = ftrace_now(cpu);
- trace_function(tr, CALLER_ADDR0, parent_ip, flags, pc);
+ __trace_function(tr, CALLER_ADDR0, parent_ip, flags, pc);
}
static inline void
@@ -204,7 +420,7 @@
local_save_flags(flags);
- trace_function(tr, ip, parent_ip, flags, preempt_count());
+ __trace_function(tr, ip, parent_ip, flags, preempt_count());
per_cpu(tracing_cpu, cpu) = 1;
@@ -238,7 +454,7 @@
atomic_inc(&data->disabled);
local_save_flags(flags);
- trace_function(tr, ip, parent_ip, flags, preempt_count());
+ __trace_function(tr, ip, parent_ip, flags, preempt_count());
check_critical_timing(tr, data, parent_ip ? : ip, cpu);
data->critical_start = 0;
atomic_dec(&data->disabled);
@@ -347,19 +563,32 @@
}
#endif /* CONFIG_PREEMPT_TRACER */
-static void start_irqsoff_tracer(struct trace_array *tr)
+static int start_irqsoff_tracer(struct trace_array *tr, int graph)
{
- register_ftrace_function(&trace_ops);
- if (tracing_is_enabled())
+ int ret = 0;
+
+ if (!graph)
+ ret = register_ftrace_function(&trace_ops);
+ else
+ ret = register_ftrace_graph(&irqsoff_graph_return,
+ &irqsoff_graph_entry);
+
+ if (!ret && tracing_is_enabled())
tracer_enabled = 1;
else
tracer_enabled = 0;
+
+ return ret;
}
-static void stop_irqsoff_tracer(struct trace_array *tr)
+static void stop_irqsoff_tracer(struct trace_array *tr, int graph)
{
tracer_enabled = 0;
- unregister_ftrace_function(&trace_ops);
+
+ if (!graph)
+ unregister_ftrace_function(&trace_ops);
+ else
+ unregister_ftrace_graph();
}
static void __irqsoff_tracer_init(struct trace_array *tr)
@@ -372,12 +601,14 @@
/* make sure that the tracer is visible */
smp_wmb();
tracing_reset_online_cpus(tr);
- start_irqsoff_tracer(tr);
+
+ if (start_irqsoff_tracer(tr, is_graph()))
+ printk(KERN_ERR "failed to start irqsoff tracer\n");
}
static void irqsoff_tracer_reset(struct trace_array *tr)
{
- stop_irqsoff_tracer(tr);
+ stop_irqsoff_tracer(tr, is_graph());
if (!save_lat_flag)
trace_flags &= ~TRACE_ITER_LATENCY_FMT;
@@ -409,9 +640,15 @@
.start = irqsoff_tracer_start,
.stop = irqsoff_tracer_stop,
.print_max = 1,
+ .print_header = irqsoff_print_header,
+ .print_line = irqsoff_print_line,
+ .flags = &tracer_flags,
+ .set_flag = irqsoff_set_flag,
#ifdef CONFIG_FTRACE_SELFTEST
.selftest = trace_selftest_startup_irqsoff,
#endif
+ .open = irqsoff_trace_open,
+ .close = irqsoff_trace_close,
};
# define register_irqsoff(trace) register_tracer(&trace)
#else
@@ -435,9 +672,15 @@
.start = irqsoff_tracer_start,
.stop = irqsoff_tracer_stop,
.print_max = 1,
+ .print_header = irqsoff_print_header,
+ .print_line = irqsoff_print_line,
+ .flags = &tracer_flags,
+ .set_flag = irqsoff_set_flag,
#ifdef CONFIG_FTRACE_SELFTEST
.selftest = trace_selftest_startup_preemptoff,
#endif
+ .open = irqsoff_trace_open,
+ .close = irqsoff_trace_close,
};
# define register_preemptoff(trace) register_tracer(&trace)
#else
@@ -463,9 +706,15 @@
.start = irqsoff_tracer_start,
.stop = irqsoff_tracer_stop,
.print_max = 1,
+ .print_header = irqsoff_print_header,
+ .print_line = irqsoff_print_line,
+ .flags = &tracer_flags,
+ .set_flag = irqsoff_set_flag,
#ifdef CONFIG_FTRACE_SELFTEST
.selftest = trace_selftest_startup_preemptirqsoff,
#endif
+ .open = irqsoff_trace_open,
+ .close = irqsoff_trace_close,
};
# define register_preemptirqsoff(trace) register_tracer(&trace)
