mirror of
https://github.com/torvalds/linux.git
synced 2024-12-26 04:42:12 +00:00
3d2626bd1f
Create a man page for libtraceevent APIs: tep_get_header_page_size(), tep_get_header_timestamp_size(), tep_is_old_format() Signed-off-by: Tzvetomir Stoyanov <tstoyanov@vmware.com> 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/linux-trace-devel/20190503091119.23399-5-tstoyanov@vmware.com Link: http://lkml.kernel.org/r/20190510200106.583928896@goodmis.org Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
103 lines
2.7 KiB
Plaintext
103 lines
2.7 KiB
Plaintext
libtraceevent(3)
|
|
================
|
|
|
|
NAME
|
|
----
|
|
tep_get_header_page_size, tep_get_header_timestamp_size, tep_is_old_format -
|
|
Get the data stored in the header page, in kernel context.
|
|
|
|
SYNOPSIS
|
|
--------
|
|
[verse]
|
|
--
|
|
*#include <event-parse.h>*
|
|
|
|
int *tep_get_header_page_size*(struct tep_handle pass:[*]_tep_);
|
|
int *tep_get_header_timestamp_size*(struct tep_handle pass:[*]_tep_);
|
|
bool *tep_is_old_format*(struct tep_handle pass:[*]_tep_);
|
|
--
|
|
DESCRIPTION
|
|
-----------
|
|
These functions retrieve information from kernel context, stored in tracefs
|
|
events/header_page. Old kernels do not have header page info, so default values
|
|
from user space context are used.
|
|
|
|
The _tep_get_header_page_size()_ function returns the size of a long integer,
|
|
in kernel context. The _tep_ argument is trace event parser context.
|
|
This information is retrieved from tracefs events/header_page, "commit" field.
|
|
|
|
The _tep_get_header_timestamp_size()_ function returns the size of timestamps,
|
|
in kernel context. The _tep_ argument is trace event parser context. This
|
|
information is retrieved from tracefs events/header_page, "timestamp" field.
|
|
|
|
The _tep_is_old_format()_ function returns true if the kernel predates
|
|
the addition of events/header_page, otherwise it returns false.
|
|
|
|
RETURN VALUE
|
|
------------
|
|
The _tep_get_header_page_size()_ function returns the size of a long integer,
|
|
in bytes.
|
|
|
|
The _tep_get_header_timestamp_size()_ function returns the size of timestamps,
|
|
in bytes.
|
|
|
|
The _tep_is_old_format()_ function returns true, if an old kernel is used to
|
|
generate the tracing data, which has no event/header_page. If the kernel is new,
|
|
or _tep_ is NULL, false is returned.
|
|
|
|
EXAMPLE
|
|
-------
|
|
[source,c]
|
|
--
|
|
#include <event-parse.h>
|
|
...
|
|
struct tep_handle *tep = tep_alloc();
|
|
...
|
|
int longsize;
|
|
int timesize;
|
|
bool old;
|
|
|
|
longsize = tep_get_header_page_size(tep);
|
|
timesize = tep_get_header_timestamp_size(tep);
|
|
old = tep_is_old_format(tep);
|
|
|
|
printf ("%s kernel is used to generate the tracing data.\n",
|
|
old?"Old":"New");
|
|
printf("The size of a long integer is %d bytes.\n", longsize);
|
|
printf("The timestamps size is %d bytes.\n", timesize);
|
|
...
|
|
--
|
|
|
|
FILES
|
|
-----
|
|
[verse]
|
|
--
|
|
*event-parse.h*
|
|
Header file to include in order to have access to the library APIs.
|
|
*-ltraceevent*
|
|
Linker switch to add when building a program that uses the library.
|
|
--
|
|
|
|
SEE ALSO
|
|
--------
|
|
_libtraceevent(3)_, _trace-cmd(1)_
|
|
|
|
AUTHOR
|
|
------
|
|
[verse]
|
|
--
|
|
*Steven Rostedt* <rostedt@goodmis.org>, author of *libtraceevent*.
|
|
*Tzvetomir Stoyanov* <tz.stoyanov@gmail.com>, author of this man page.
|
|
--
|
|
REPORTING BUGS
|
|
--------------
|
|
Report bugs to <linux-trace-devel@vger.kernel.org>
|
|
|
|
LICENSE
|
|
-------
|
|
libtraceevent is Free Software licensed under the GNU LGPL 2.1
|
|
|
|
RESOURCES
|
|
---------
|
|
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
|