On Fri, 12 Apr 2019 16:37:45 +0300
Tzvetomir Stoyanov <tstoyanov@xxxxxxxxxx> wrote:
> 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@xxxxxxxxxx>
> ---
> .../libtraceevent-header_page.txt | 105 ++++++++++++++++++
> 1 file changed, 105 insertions(+)
> create mode 100644 tools/lib/traceevent/Documentation/libtraceevent-header_page.txt
>
> diff --git a/tools/lib/traceevent/Documentation/libtraceevent-header_page.txt b/tools/lib/traceevent/Documentation/libtraceevent-header_page.txt
> new file mode 100644
> index 000000000000..e1bd664ac123
> --- /dev/null
> +++ b/tools/lib/traceevent/Documentation/libtraceevent-header_page.txt
> @@ -0,0 +1,105 @@
> +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
> +/sys/kernel/debug/tracing/events/header_page. Old kernels do not have header
Let's avoid using full path names. This should be:
stored in the tracefs events/header_page.
> +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 /sys/kernel/debug/tracing/events/header_page,
Same here.
> + "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 /sys/kernel/debug/tracing/events/header_page,
and here.
> + "timestamp" field.
> +
> +The _tep_is_old_format()_ function returns if the kernel is old one and has no
The _tep_is_old_format()_ function returns true if the kernel predates
the addition of events/header_page, otherwise it returns false.
> +/sys/kernel/debug/tracing/events/header_page.
> +
> +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
> +/sys/kernel/debug/tracing/events/header_page. If the kernel is new, or _tep_ is
Just say "no event/header_page"
-- Steve
> +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@xxxxxxxxxxx>, author of *libtraceevent*.
> +*Tzvetomir Stoyanov* <tz.stoyanov@xxxxxxxxx>, author of this man page.
> +--
> +REPORTING BUGS
> +--------------
> +Report bugs to <linux-trace-devel@xxxxxxxxxxxxxxx>
> +
> +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
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