ftrace: Add set_graph_notrace filter
The set_graph_notrace filter is analogous to set_ftrace_notrace and
can be used for eliminating uninteresting part of function graph trace
output. It also works with set_graph_function nicely.
# cd /sys/kernel/debug/tracing/
# echo do_page_fault > set_graph_function
# perf ftrace live true
2) | do_page_fault() {
2) | __do_page_fault() {
2) 0.381 us | down_read_trylock();
2) 0.055 us | __might_sleep();
2) 0.696 us | find_vma();
2) | handle_mm_fault() {
2) | handle_pte_fault() {
2) | __do_fault() {
2) | filemap_fault() {
2) | find_get_page() {
2) 0.033 us | __rcu_read_lock();
2) 0.035 us | __rcu_read_unlock();
2) 1.696 us | }
2) 0.031 us | __might_sleep();
2) 2.831 us | }
2) | _raw_spin_lock() {
2) 0.046 us | add_preempt_count();
2) 0.841 us | }
2) 0.033 us | page_add_file_rmap();
2) | _raw_spin_unlock() {
2) 0.057 us | sub_preempt_count();
2) 0.568 us | }
2) | unlock_page() {
2) 0.084 us | page_waitqueue();
2) 0.126 us | __wake_up_bit();
2) 1.117 us | }
2) 7.729 us | }
2) 8.397 us | }
2) 8.956 us | }
2) 0.085 us | up_read();
2) + 12.745 us | }
2) + 13.401 us | }
...
# echo handle_mm_fault > set_graph_notrace
# perf ftrace live true
1) | do_page_fault() {
1) | __do_page_fault() {
1) 0.205 us | down_read_trylock();
1) 0.041 us | __might_sleep();
1) 0.344 us | find_vma();
1) 0.069 us | up_read();
1) 4.692 us | }
1) 5.311 us | }
...
Link: http://lkml.kernel.org/r/1381739066-7531-5-git-send-email-namhyung@kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 26a229a..44e826a 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -3776,7 +3776,9 @@
static DEFINE_MUTEX(graph_lock);
int ftrace_graph_count;
+int ftrace_graph_notrace_count;
unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
+unsigned long ftrace_graph_notrace_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
struct ftrace_graph_data {
unsigned long *table;
@@ -3891,6 +3893,26 @@
}
static int
+ftrace_graph_notrace_open(struct inode *inode, struct file *file)
+{
+ struct ftrace_graph_data *fgd;
+
+ if (unlikely(ftrace_disabled))
+ return -ENODEV;
+
+ fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
+ if (fgd == NULL)
+ return -ENOMEM;
+
+ fgd->table = ftrace_graph_notrace_funcs;
+ fgd->size = FTRACE_GRAPH_MAX_FUNCS;
+ fgd->count = &ftrace_graph_notrace_count;
+ fgd->seq_ops = &ftrace_graph_seq_ops;
+
+ return __ftrace_graph_open(inode, file, fgd);
+}
+
+static int
ftrace_graph_release(struct inode *inode, struct file *file)
{
if (file->f_mode & FMODE_READ) {
@@ -4011,6 +4033,14 @@
.llseek = ftrace_filter_lseek,
.release = ftrace_graph_release,
};
+
+static const struct file_operations ftrace_graph_notrace_fops = {
+ .open = ftrace_graph_notrace_open,
+ .read = seq_read,
+ .write = ftrace_graph_write,
+ .llseek = ftrace_filter_lseek,
+ .release = ftrace_graph_release,
+};
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
@@ -4032,6 +4062,9 @@
trace_create_file("set_graph_function", 0444, d_tracer,
NULL,
&ftrace_graph_fops);
+ trace_create_file("set_graph_notrace", 0444, d_tracer,
+ NULL,
+ &ftrace_graph_notrace_fops);
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
return 0;