[PATCH 14/44] tools lib traceevent: Add more debugging to see various internal ring buffer entries

Arnaldo Carvalho de Melo
2019-04-02T16:06:51Z

From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>

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 (VMware) <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Tzvetomir Stoyanov <tstoyanov@vmware.com>
Link: http://lkml.kernel.org/r/20190401164343.257591565@goodmis.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/lib/traceevent/kbuffer-parse.c | 49 ++++++++++++++++++++++++++++
tools/lib/traceevent/kbuffer.h | 13 ++++++++
2 files changed, 62 insertions(+)

diff --git a/tools/lib/traceevent/kbuffer-parse.c b/tools/lib/traceevent/kbuffer-parse.c
index af2a1f3b7424..b887e7437d67 100644
--- a/tools/lib/traceevent/kbuffer-parse.c
+++ b/tools/lib/traceevent/kbuffer-parse.c
@@ -727,3 +727,52 @@ 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/tools/lib/traceevent/kbuffer.h b/tools/lib/traceevent/kbuffer.h
index 03dce757553f..ed4d697fc137 100644
--- a/tools/lib/traceevent/kbuffer.h
+++ b/tools/lib/traceevent/kbuffer.h
@@ -65,4 +65,17 @@ 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 */
--
2.20.1