tep_data_type - Man Page

#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