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libtraceevent(3)
================
NAME
----
tep_data_type, tep_data_pid,tep_data_preempt_count, tep_data_flags -
Extract common fields from a record.
SYNOPSIS
--------
[verse]
--
*#include <event-parse.h>*
enum *trace_flag_type* {
_TRACE_FLAG_IRQS_OFF_,
_TRACE_FLAG_IRQS_NOSUPPORT_,
_TRACE_FLAG_NEED_RESCHED_,
_TRACE_FLAG_HARDIRQ_,
_TRACE_FLAG_SOFTIRQ_,
};
int *tep_data_type*(struct tep_handle pass:[*]_tep_, struct tep_record pass:[*]_rec_);
int *tep_data_pid*(struct tep_handle pass:[*]_tep_, struct tep_record pass:[*]_rec_);
int *tep_data_preempt_count*(struct tep_handle pass:[*]_tep_, struct tep_record pass:[*]_rec_);
int *tep_data_flags*(struct tep_handle pass:[*]_tep_, struct tep_record pass:[*]_rec_);
--
DESCRIPTION
-----------
This set of functions can be used to extract common fields from a record.
The _tep_data_type()_ function gets the event id from the record _rec_.
It reads the "common_type" field. The _tep_ argument is the trace event parser
context.
The _tep_data_pid()_ function gets the process id from the record _rec_.
It reads the "common_pid" field. The _tep_ argument is the trace event parser
context.
The _tep_data_preempt_count()_ function gets the preemption count from the
record _rec_. It reads the "common_preempt_count" field. The _tep_ argument is
the trace event parser context.
The _tep_data_flags()_ function gets the latency flags from the record _rec_.
It reads the "common_flags" field. The _tep_ argument is the trace event parser
context. Supported latency flags are:
[verse]
--
_TRACE_FLAG_IRQS_OFF_, Interrupts are disabled.
_TRACE_FLAG_IRQS_NOSUPPORT_, Reading IRQ flag is not supported by the architecture.
_TRACE_FLAG_NEED_RESCHED_, Task needs rescheduling.
_TRACE_FLAG_HARDIRQ_, Hard IRQ is running.
_TRACE_FLAG_SOFTIRQ_, Soft IRQ is running.
--
RETURN VALUE
------------
The _tep_data_type()_ function returns an integer, representing the event id.
The _tep_data_pid()_ function returns an integer, representing the process id
The _tep_data_preempt_count()_ function returns an integer, representing the
preemption count.
The _tep_data_flags()_ function returns an integer, representing the latency
flags. Look at the _trace_flag_type_ enum for supported flags.
All these functions in case of an error return a negative integer.
EXAMPLE
-------
[source,c]
--
#include <event-parse.h>
...
struct tep_handle *tep = tep_alloc();
...
void process_record(struct tep_record *record)
{
int data;
data = tep_data_type(tep, record);
if (data >= 0) {
/* Got the ID of the event */
}
data = tep_data_pid(tep, record);
if (data >= 0) {
/* Got the process ID */
}
data = tep_data_preempt_count(tep, record);
if (data >= 0) {
/* Got the preemption count */
}
data = tep_data_flags(tep, record);
if (data >= 0) {
/* Got the latency flags */
}
}
...
--
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
|
