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Subject[PATCH 01/23 v3] tools lib traceevent: Add API to read time information from kbuffer
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>

Add the functions kbuffer_subbuf_timestamp() and kbuffer_ptr_delta() to get
the timing data stored in the ring buffer that is used to produced the time
stamps of the records.

This is useful for tools like trace-cmd to be able to display the content of
the read data to understand why the records show the time stamps that they
do.

Link: http://lore.kernel.org/linux-trace-devel/20200625100516.365338-2-tz.stoyanov@gmail.com

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
[ Ported from trace-cmd.git ]
Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
tools/lib/traceevent/kbuffer-parse.c | 28 ++++++++++++++++++++++++++++
tools/lib/traceevent/kbuffer.h | 2 ++
2 files changed, 30 insertions(+)

diff --git a/tools/lib/traceevent/kbuffer-parse.c b/tools/lib/traceevent/kbuffer-parse.c
index 27f3b07fdae8..583db99aee94 100644
--- a/tools/lib/traceevent/kbuffer-parse.c
+++ b/tools/lib/traceevent/kbuffer-parse.c
@@ -546,6 +546,34 @@ int kbuffer_load_subbuffer(struct kbuffer *kbuf, void *subbuffer)
return 0;
}

+/**
+ * kbuffer_subbuf_timestamp - read the timestamp from a sub buffer
+ * @kbuf: The kbuffer to load
+ * @subbuf: The subbuffer to read from.
+ *
+ * Return the timestamp from a subbuffer.
+ */
+unsigned long long kbuffer_subbuf_timestamp(struct kbuffer *kbuf, void *subbuf)
+{
+ return kbuf->read_8(subbuf);
+}
+
+/**
+ * kbuffer_ptr_delta - read the delta field from a record
+ * @kbuf: The kbuffer to load
+ * @ptr: The record in the buffe.
+ *
+ * Return the timestamp delta from a record
+ */
+unsigned int kbuffer_ptr_delta(struct kbuffer *kbuf, void *ptr)
+{
+ unsigned int type_len_ts;
+
+ type_len_ts = read_4(kbuf, ptr);
+ return ts4host(kbuf, type_len_ts);
+}
+
+
/**
* kbuffer_read_event - read the next event in the kbuffer subbuffer
* @kbuf: The kbuffer to read from
diff --git a/tools/lib/traceevent/kbuffer.h b/tools/lib/traceevent/kbuffer.h
index ed4d697fc137..5fa8292e341b 100644
--- a/tools/lib/traceevent/kbuffer.h
+++ b/tools/lib/traceevent/kbuffer.h
@@ -49,6 +49,8 @@ int kbuffer_load_subbuffer(struct kbuffer *kbuf, void *subbuffer);
void *kbuffer_read_event(struct kbuffer *kbuf, unsigned long long *ts);
void *kbuffer_next_event(struct kbuffer *kbuf, unsigned long long *ts);
unsigned long long kbuffer_timestamp(struct kbuffer *kbuf);
+unsigned long long kbuffer_subbuf_timestamp(struct kbuffer *kbuf, void *subbuf);
+unsigned int kbuffer_ptr_delta(struct kbuffer *kbuf, void *ptr);

void *kbuffer_translate_data(int swap, void *data, unsigned int *size);

--
2.26.2

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