NAME

       tep_print_event - Writes event information into a trace sequence.

SYNOPSIS

       #include <event-parse.h>
       #include <trace-seq.h>

       void tep_print_event(struct tep_handle *tep, struct trace_seq*s, struct tep_record *record, const char *fmt, ...)

DESCRIPTION

       The tep_print_event() function parses the event information of the given record and writes
       it into the trace sequence s, according to the format string fmt. The desired information
       is specified after the format string. The fmt is printf-like format string, following
       arguments are supported:

                   TEP_PRINT_PID, "%d"  - PID of the event.
                   TEP_PRINT_CPU, "%d"  - Event CPU.
                   TEP_PRINT_COMM, "%s" - Event command string.
                   TEP_PRINT_NAME, "%s" - Event name.
                   TEP_PRINT_LATENCY, "%s" - Latency of the event. It prints 4 or more
                                   fields - interrupt state, scheduling state,
                                   current context, and preemption count.
                                   Field 1 is the interrupt enabled state:
                                           d : Interrupts are disabled
                                           . : Interrupts are enabled
                                           X : The architecture does not support this
                                               information
                                   Field 2 is the "need resched" state.
                                           N : The task is set to call the scheduler when
                                               possible, as another higher priority task
                                               may need to be scheduled in.
                                           . : The task is not set to call the scheduler.
                                   Field 3 is the context state.
                                           . : Normal context
                                           s : Soft interrupt context
                                           h : Hard interrupt context
                                           H : Hard interrupt context which triggered
                                               during soft interrupt context.
                                           z : NMI context
                                           Z : NMI context which triggered during hard
                                               interrupt context
                                   Field 4 is the preemption count.
                                           . : The preempt count is zero.
                                   On preemptible kernels (where the task can be scheduled
                                   out in arbitrary locations while in kernel context), the
                                   preempt count, when non zero, will prevent the kernel
                                   from scheduling out the current task. The preempt count
                                   number is displayed when it is not zero.
                                   Depending on the kernel, it may show other fields
                                   (lock depth, or migration disabled, which are unique to
                                   specialized kernels).
                   TEP_PRINT_TIME, %d - event time stamp. A divisor and precision can be
                                   specified as part of this format string:
                                   "%precision.divisord". Example:
                                   "%3.1000d" - divide the time by 1000 and print the first
                                   3 digits before the dot. Thus, the time stamp
                                   "123456000" will be printed as "123.456"
                   TEP_PRINT_INFO, "%s" - event information.
                   TEP_PRINT_INFO_RAW, "%s" - event information, in raw format.

EXAMPLE

           #include <event-parse.h>
           #include <trace-seq.h>
           ...
           struct trace_seq seq;
           trace_seq_init(&seq);
           struct tep_handle *tep = tep_alloc();
           ...
           void print_my_event(struct tep_record *record)
           {
                   trace_seq_reset(&seq);
                   tep_print_event(tep, s, record, "%16s-%-5d [%03d] %s %6.1000d %s %s",
                                   TEP_PRINT_COMM, TEP_PRINT_PID, TEP_PRINT_CPU,
                                   TEP_PRINT_LATENCY, TEP_PRINT_TIME, TEP_PRINT_NAME,
                                   TEP_PRINT_INFO);
           }
           ...

FILES

           event-parse.h
                   Header file to include in order to have access to the library APIs.
           trace-seq.h
                   Header file to include in order to have access to trace sequences related APIs.
                   Trace sequences are used to allow a function to call several other functions
                   to create a string of data to use.
           -ltraceevent
                   Linker switch to add when building a program that uses the library.

SEE ALSO

       libtraceevent(3), trace-cmd(1)

AUTHOR

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

REPORTING BUGS

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

LICENSE

       libtraceevent is Free Software licensed under the GNU LGPL 2.1

RESOURCES

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

NOTES

        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