trace-cmd: Add more debugging to see various internal ring buffer entries

When trace-cmd report --debug is set, show the internal ring buffer entries
like time-extends and padding. This requires adding new kbuffer API to
retrieve these items.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

5 files changed, 137 insertions, 1 deletions

diff --git a/kbuffer-parse.c b/kbuffer-parse.c
index fca326ca..cd13a921 100644
--- a/kbuffer-parse.c
+++ b/kbuffer-parse.c
@@ -767,3 +767,52 @@ int kbuffer_start_of_data(struct kbuffer *kbuf)
 {
 	return kbuf->start;
 }
+
+/**
+ * kbuffer_raw_get - get raw buffer info
+ * @kbuf:	The kbuffer
+ * @subbuf:	Start of mapped subbuffer
+ * @info:	Info descriptor to fill in
+ *
+ * For debugging. This can return internals of the ring buffer.
+ * Expects to have info->next set to what it will read.
+ * The type, length and timestamp delta will be filled in, and
+ * @info->next will be updated to the next element.
+ * The @subbuf is used to know if the info is passed the end of
+ * data and NULL will be returned if it is.
+ */
+struct kbuffer_raw_info *
+kbuffer_raw_get(struct kbuffer *kbuf, void *subbuf, struct kbuffer_raw_info *info)
+{
+	unsigned long long flags;
+	unsigned long long delta;
+	unsigned int type_len;
+	unsigned int size;
+	int start;
+	int length;
+	void *ptr = info->next;
+
+	if (!kbuf || !subbuf)
+		return NULL;
+
+	if (kbuf->flags & KBUFFER_FL_LONG_8)
+		start = 16;
+	else
+		start = 12;
+
+	flags = read_long(kbuf, subbuf + 8);
+	size = (unsigned int)flags & COMMIT_MASK;
+
+	if (ptr < subbuf || ptr >= subbuf + start + size)
+		return NULL;
+
+	type_len = translate_data(kbuf, ptr, &ptr, &delta, &length);
+
+	info->next = ptr + length;
+
+	info->type = type_len;
+	info->delta = delta;
+	info->length = length;
+
+	return info;
+}
diff --git a/kbuffer.h b/kbuffer.h
index 45dbeca6..5fa8292e 100644
--- a/kbuffer.h
+++ b/kbuffer.h
@@ -67,4 +67,17 @@ int kbuffer_subbuffer_size(struct kbuffer *kbuf);
 void kbuffer_set_old_format(struct kbuffer *kbuf);
 int kbuffer_start_of_data(struct kbuffer *kbuf);
 
+/* Debugging */
+
+struct kbuffer_raw_info {
+	int			type;
+	int			length;
+	unsigned long long	delta;
+	void			*next;
+};
+
+/* Read raw data */
+struct kbuffer_raw_info *kbuffer_raw_get(struct kbuffer *kbuf, void *subbuf,
+					 struct kbuffer_raw_info *info);
+
 #endif /* _K_BUFFER_H */
diff --git a/trace-cmd.h b/trace-cmd.h
index a6983448..c9b9b955 100644
--- a/trace-cmd.h
+++ b/trace-cmd.h
@@ -320,4 +320,13 @@ void tracecmd_free_hooks(struct hook_list *hooks);
 /* --- Hack! --- */
 int tracecmd_blk_hack(struct tracecmd_input *handle);
 
+
+/* --- Debugging --- */
+struct kbuffer *tracecmd_record_kbuf(struct tracecmd_input *handle,
+				     struct pevent_record *record);
+void *tracecmd_record_page(struct tracecmd_input *handle,
+			   struct pevent_record *record);
+void *tracecmd_record_offset(struct tracecmd_input *handle,
+			     struct pevent_record *record);
+
 #endif /* _TRACE_CMD_H */
diff --git a/trace-input.c b/trace-input.c
index a7e0ff2a..76f03ee3 100644
--- a/trace-input.c
+++ b/trace-input.c
@@ -2847,6 +2847,34 @@ unsigned int tracecmd_record_ts_delta(struct tracecmd_input *handle,
 	return kbuffer_ptr_delta(kbuf, page->map + offset);
 }
 
+struct kbuffer *tracecmd_record_kbuf(struct tracecmd_input *handle,
+				     struct pevent_record *record)
+{
+	return handle->cpu_data[record->cpu].kbuf;
+}
+
+void *tracecmd_record_page(struct tracecmd_input *handle,
+			   struct pevent_record *record)
+{
+	struct page *page = record->priv;
+
+	return page ? page->map : NULL;
+}
+
+void *tracecmd_record_offset(struct tracecmd_input *handle,
+			     struct pevent_record *record)
+{
+	struct page *page = record->priv;
+	int offset;
+
+	if (!page)
+		return NULL;
+
+	offset = record->offset - page->offset;
+
+	return page->map + offset;
+}
+
 int tracecmd_buffer_instances(struct tracecmd_input *handle)
 {
 	return handle->nr_buffers;
diff --git a/trace-read.c b/trace-read.c
index e496ef0f..fe8f98b7 100644
--- a/trace-read.c
+++ b/trace-read.c
@@ -37,6 +37,7 @@
 
 #include "trace-local.h"
 #include "trace-hash.h"
+#include "kbuffer.h"
 #include "list.h"
 
 static struct filter_str {
@@ -774,9 +775,45 @@ void trace_show_data(struct tracecmd_input *handle, struct pevent_record *record
 	pevent_print_event(pevent, &s, record, use_trace_clock);
 	if (s.len && *(s.buffer + s.len - 1) == '\n')
 		s.len--;
-	if (debug)
+	if (debug) {
+		struct kbuffer *kbuf;
+		struct kbuffer_raw_info info;
+		void *page;
+		void *offset;
+
 		trace_seq_printf(&s, " [%d]",
 				 tracecmd_record_ts_delta(handle, record));
+		kbuf = tracecmd_record_kbuf(handle, record);
+		page = tracecmd_record_page(handle, record);
+		offset = tracecmd_record_offset(handle, record);
+
+		if (kbuf && page && offset) {
+			struct kbuffer_raw_info *pi = &info;
+
+			/* We need to get the record raw data to get next */
+			pi->next = offset;
+			pi = kbuffer_raw_get(kbuf, page, pi);
+			while ((pi = kbuffer_raw_get(kbuf, page, pi))) {
+				if (pi->type < KBUFFER_TYPE_PADDING)
+					break;
+				switch (pi->type) {
+				case KBUFFER_TYPE_PADDING:
+					trace_seq_printf(&s, "\n PADDING: ");
+					break;
+				case KBUFFER_TYPE_TIME_EXTEND:
+					trace_seq_printf(&s, "\n TIME EXTEND: ");
+					break;
+				case KBUFFER_TYPE_TIME_STAMP:
+					trace_seq_printf(&s, "\n TIME STAMP?: ");
+					break;
+				}
+				trace_seq_printf(&s, "delta:%lld length:%d",
+						 pi->delta,
+						 pi->length);
+			}
+		}
+	}
+		
 	trace_seq_do_printf(&s);
 	trace_seq_destroy(&s);