Man page - tep_data_type(3)

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Manual

LIBTRACEEVENT(3) libtraceevent Manual LIBTRACEEVENT(3)

tep_data_type, tep_data_pid, tep_data_preempt_count, tep_data_flags - Extract common fields from a record.

#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 *tep, struct tep_record *rec);
int tep_data_pid(struct tep_handle *tep, struct tep_record *rec);
int tep_data_preempt_count(struct tep_handle *tep, struct tep_record *rec);
int tep_data_flags(struct tep_handle *tep, struct tep_record *rec);

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:



        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.

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.

#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 */


        }
}
...

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.

libtraceevent(3), trace-cmd(1)

Steven Rostedt <rostedt@goodmis.org[1]>, author of libtraceevent.
Tzvetomir Stoyanov <tz.stoyanov@gmail.com[2]>, author of this man page.

Report bugs to <linux-trace-devel@vger.kernel.org[3]>

libtraceevent is Free Software licensed under the GNU LGPL 2.1

https://git.kernel.org/pub/scm/libs/libtrace/libtraceevent.git/

1.
rostedt@goodmis.org
mailto:rostedt@goodmis.org
2.
tz.stoyanov@gmail.com
mailto:tz.stoyanov@gmail.com
3.
linux-trace-devel@vger.kernel.org
mailto:linux-trace-devel@vger.kernel.org
12/24/2024 libtraceevent 1.8.4