[PATCH 10/23 v3] tools lib traceevent: Add offset option for function plugin

From: Steven Rostedt
Date: Tue Jul 21 2020 - 21:18:50 EST


From: "Steven Rostedt (VMware)" <rostedt@xxxxxxxxxxx>

When the offset option is set for the function plugin enabled, it will
display the offset of the functions along with their names. This helps in
finding exactly where a function was called by its parent.

trace-cmd report -O parent -O offset
[..]
rcuc/163-1330 [163] 740.653251: function: _raw_spin_lock+0x0 <-- rcu_cpu_kthread+0x4d8

Link: http://lore.kernel.org/linux-trace-devel/20200702174950.123454-2-tz.stoyanov@xxxxxxxxx

Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
[ Ported from trace-cmd.git ]
Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@xxxxxxxxx>
Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
---
.../lib/traceevent/plugins/plugin_function.c | 24 +++++++++++++++++--
1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/tools/lib/traceevent/plugins/plugin_function.c b/tools/lib/traceevent/plugins/plugin_function.c
index 7770fcb78e0f..cafddd6be983 100644
--- a/tools/lib/traceevent/plugins/plugin_function.c
+++ b/tools/lib/traceevent/plugins/plugin_function.c
@@ -49,6 +49,13 @@ struct tep_plugin_option plugin_options[] =
"Try to show function call indents, based on parents",
.set = 1,
},
+ {
+ .name = "offset",
+ .plugin_alias = "ftrace",
+ .description =
+ "Show function names as well as their offsets",
+ .set = 0,
+ },
{
.name = NULL,
}
@@ -56,6 +63,7 @@ struct tep_plugin_option plugin_options[] =

static struct tep_plugin_option *ftrace_parent = &plugin_options[0];
static struct tep_plugin_option *ftrace_indent = &plugin_options[1];
+static struct tep_plugin_option *ftrace_offset = &plugin_options[2];

static void add_child(struct func_stack *stack, const char *child, int pos)
{
@@ -123,6 +131,18 @@ static int add_and_get_index(const char *parent, const char *child, int cpu)
return 0;
}

+static void show_function(struct trace_seq *s, struct tep_handle *tep,
+ const char *func, unsigned long long function)
+{
+ unsigned long long offset;
+
+ trace_seq_printf(s, "%s", func);
+ if (ftrace_offset->set) {
+ offset = tep_find_function_address(tep, function);
+ trace_seq_printf(s, "+0x%x ", (int)(function - offset));
+ }
+}
+
static int function_handler(struct trace_seq *s, struct tep_record *record,
struct tep_event *event, void *context)
{
@@ -149,14 +169,14 @@ static int function_handler(struct trace_seq *s, struct tep_record *record,
trace_seq_printf(s, "%*s", index*3, "");

if (func)
- trace_seq_printf(s, "%s", func);
+ show_function(s, tep, func, function);
else
trace_seq_printf(s, "0x%llx", function);

if (ftrace_parent->set) {
trace_seq_printf(s, " <-- ");
if (parent)
- trace_seq_printf(s, "%s", parent);
+ show_function(s, tep, parent, pfunction);
else
trace_seq_printf(s, "0x%llx", pfunction);
}
--
2.26.2