[-tip,-v11,11/11] tracing: Add kprobes event profiling interface
diff mbox

Message ID 20090709202327.13223.16418.stgit@localhost.localdomain
State New, archived
Headers show

Commit Message

Masami Hiramatsu July 9, 2009, 8:23 p.m. UTC
Add profiling interaces for each kprobes event.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
---

 Documentation/trace/kprobetrace.txt |    8 ++++++
 kernel/trace/trace_kprobe.c         |   48 +++++++++++++++++++++++++++++++++++
 2 files changed, 56 insertions(+), 0 deletions(-)

Comments

Li Zefan July 10, 2009, 6:46 a.m. UTC | #1
> +Event Profiling
> +---------------
> + You can check the total number of probe hits and probe miss-hits via
> +/sys/kernel/debug/tracing/kprobe_profile.
> + The fist column is event name, the second is the number of probe hits,

s/fist/first

> +the third is the number of probe miss-hits.
> +
> +
...
> +/* Probes profiling interfaces */
> +static int profile_seq_show(struct seq_file *m, void *v)
> +{
> +	struct trace_probe *tp = v;
> +
> +	if (tp == NULL)
> +		return 0;
> +

tp will never be NULL, which is guaranteed by seq_file

> +	seq_printf(m, "%s", tp->call.name);
> +
> +	seq_printf(m, "\t%8lu %8lu\n", tp->nhits,
> +		   probe_is_return(tp) ? tp->rp.kp.nmissed : tp->kp.nmissed);
> +
> +	return 0;
> +}
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Masami Hiramatsu July 10, 2009, 7:59 p.m. UTC | #2
Hi,

Li Zefan wrote:
>> +Event Profiling
>> +---------------
>> + You can check the total number of probe hits and probe miss-hits via
>> +/sys/kernel/debug/tracing/kprobe_profile.
>> + The fist column is event name, the second is the number of probe hits,
> 
> s/fist/first

Oops, fixed.

> 
>> +the third is the number of probe miss-hits.
>> +
>> +
> ...
>> +/* Probes profiling interfaces */
>> +static int profile_seq_show(struct seq_file *m, void *v)
>> +{
>> +	struct trace_probe *tp = v;
>> +
>> +	if (tp == NULL)
>> +		return 0;
>> +
> 
> tp will never be NULL, which is guaranteed by seq_file

OK, fixed.

>> +	seq_printf(m, "%s", tp->call.name);
>> +
>> +	seq_printf(m, "\t%8lu %8lu\n", tp->nhits,
>> +		   probe_is_return(tp) ? tp->rp.kp.nmissed : tp->kp.nmissed);
>> +
>> +	return 0;
>> +}

Thank you for review!

Patch
diff mbox

diff --git a/Documentation/trace/kprobetrace.txt b/Documentation/trace/kprobetrace.txt
index 437ad49..d386d96 100644
--- a/Documentation/trace/kprobetrace.txt
+++ b/Documentation/trace/kprobetrace.txt
@@ -69,6 +69,14 @@  filter:
  names and field names for describing filters.
 
 
+Event Profiling
+---------------
+ You can check the total number of probe hits and probe miss-hits via
+/sys/kernel/debug/tracing/kprobe_profile.
+ The fist column is event name, the second is the number of probe hits,
+the third is the number of probe miss-hits.
+
+
 Usage examples
 --------------
 To add a probe as a new event, write a new definition to kprobe_events
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 9c6ffcc..cbff9d5 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -174,6 +174,7 @@  struct trace_probe {
 		struct kprobe		kp;
 		struct kretprobe	rp;
 	};
+	unsigned long 		nhits;
 	const char		*symbol;	/* symbol name */
 	struct ftrace_event_call	call;
 	unsigned int		nr_args;
@@ -762,6 +763,42 @@  static const struct file_operations kprobe_events_ops = {
 	.write		= probes_write,
 };
 
+/* Probes profiling interfaces */
+static int profile_seq_show(struct seq_file *m, void *v)
+{
+	struct trace_probe *tp = v;
+
+	if (tp == NULL)
+		return 0;
+
+	seq_printf(m, "%s", tp->call.name);
+
+	seq_printf(m, "\t%8lu %8lu\n", tp->nhits,
+		   probe_is_return(tp) ? tp->rp.kp.nmissed : tp->kp.nmissed);
+
+	return 0;
+}
+
+static const struct seq_operations profile_seq_op = {
+	.start  = probes_seq_start,
+	.next   = probes_seq_next,
+	.stop   = probes_seq_stop,
+	.show   = profile_seq_show
+};
+
+static int profile_open(struct inode *inode, struct file *file)
+{
+	return seq_open(file, &profile_seq_op);
+}
+
+static const struct file_operations kprobe_profile_ops = {
+	.owner          = THIS_MODULE,
+	.open           = profile_open,
+	.read           = seq_read,
+	.llseek         = seq_lseek,
+	.release        = seq_release,
+};
+
 /* Kprobe handler */
 static __kprobes int kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs)
 {
@@ -772,6 +809,8 @@  static __kprobes int kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs)
 	unsigned long irq_flags;
 	struct ftrace_event_call *call = &tp->call;
 
+	tp->nhits++;
+
 	local_save_flags(irq_flags);
 	pc = preempt_count();
 
@@ -1145,9 +1184,18 @@  static __init int init_kprobe_trace(void)
 	entry = debugfs_create_file("kprobe_events", 0644, d_tracer,
 				    NULL, &kprobe_events_ops);
 
+	/* Event list interface */
 	if (!entry)
 		pr_warning("Could not create debugfs "
 			   "'kprobe_events' entry\n");
+
+	/* Profile interface */
+	entry = debugfs_create_file("kprobe_profile", 0444, d_tracer,
+				    NULL, &kprobe_profile_ops);
+
+	if (!entry)
+		pr_warning("Could not create debugfs "
+			   "'kprobe_profile' entry\n");
 	return 0;
 }
 fs_initcall(init_kprobe_trace);