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tools lib traceevent: Add API to read time information from kbuffer

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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 (VMware) <rostedt@goodmis.org>
[ Ported from trace-cmd.git ]
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: linux-trace-devel@vger.kernel.org
Link: http://lore.kernel.org/lkml/20200702185703.619656282@goodmis.org
Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Steven Rostedt (Red Hat)
2020-07-02 14:53:45 -04:00
committed by Arnaldo Carvalho de Melo
parent f18d5cf86c
commit 374855c5e4
2 changed files with 30 additions and 0 deletions
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28
tools/lib/traceevent/kbuffer-parse.c
View File

@ -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

2
tools/lib/traceevent/kbuffer.h
View File

@ -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);