1LIBTRACEEVENT(3) libtraceevent Manual LIBTRACEEVENT(3)
2
6 tep_data_type, tep_data_pid, tep_data_preempt_count, tep_data_flags -
7 Extract common fields from a record.
8
10 #include <event-parse.h>
11 enum trace_flag_type {
13 TRACE_FLAG_IRQS_OFF,
14 TRACE_FLAG_IRQS_NOSUPPORT,
15 TRACE_FLAG_NEED_RESCHED,
16 TRACE_FLAG_HARDIRQ,
17 TRACE_FLAG_SOFTIRQ,
18 };
19 int tep_data_type(struct tep_handle *tep, struct tep_record *rec);
21 int tep_data_pid(struct tep_handle *tep, struct tep_record *rec);
22 int tep_data_preempt_count(struct tep_handle *tep, struct tep_record *rec);
23 int tep_data_flags(struct tep_handle *tep, struct tep_record *rec);
24
26 This set of functions can be used to extract common fields from a
27 record.
28 The tep_data_type() function gets the event id from the record rec. It
30 reads the "common_type" field. The tep argument is the trace event
31 parser context.
32 The tep_data_pid() function gets the process id from the record rec. It
34 reads the "common_pid" field. The tep argument is the trace event
35 parser context.
36 The tep_data_preempt_count() function gets the preemption count from
38 the record rec. It reads the "common_preempt_count" field. The tep
39 argument is the trace event parser context.
40 The tep_data_flags() function gets the latency flags from the record
42 rec. It reads the "common_flags" field. The tep argument is the trace
43 event parser context. Supported latency flags are:
44 TRACE_FLAG_IRQS_OFF, Interrupts are disabled.
46 TRACE_FLAG_IRQS_NOSUPPORT, Reading IRQ flag is not supported by the architecture.
47 TRACE_FLAG_NEED_RESCHED, Task needs rescheduling.
48 TRACE_FLAG_HARDIRQ, Hard IRQ is running.
49 TRACE_FLAG_SOFTIRQ, Soft IRQ is running.
50
52 The tep_data_type() function returns an integer, representing the event
53 id.
54 The tep_data_pid() function returns an integer, representing the
56 process id
57 The tep_data_preempt_count() function returns an integer, representing
59 the preemption count.
60 The tep_data_flags() function returns an integer, representing the
62 latency flags. Look at the trace_flag_type enum for supported flags.
63 All these functions in case of an error return a negative integer.
65
67 #include <event-parse.h>
68 ...
69 struct tep_handle *tep = tep_alloc();
70 ...
71 void process_record(struct tep_record *record)
72 {
73 int data;
74 data = tep_data_type(tep, record);
76 if (data >= 0) {
77 /* Got the ID of the event */
78 }
79 data = tep_data_pid(tep, record);
81 if (data >= 0) {
82 /* Got the process ID */
83 }
84 data = tep_data_preempt_count(tep, record);
86 if (data >= 0) {
87 /* Got the preemption count */
88 }
89 data = tep_data_flags(tep, record);
91 if (data >= 0) {
92 /* Got the latency flags */
93 }
94 }
95 ...
96
98 event-parse.h
99 Header file to include in order to have access to the library APIs.
100 -ltraceevent
101 Linker switch to add when building a program that uses the library.
102
104 libtraceevent(3), trace-cmd(1)
105
107 Steven Rostedt <rostedt@goodmis.org[1]>, author of libtraceevent.
108 Tzvetomir Stoyanov <tz.stoyanov@gmail.com[2]>, author of this man page.
109
111 Report bugs to <linux-trace-devel@vger.kernel.org[3]>
112
114 libtraceevent is Free Software licensed under the GNU LGPL 2.1
115
117 https://git.kernel.org/pub/scm/libs/libtrace/libtraceevent.git/
118
120 1. rostedt@goodmis.org
121 mailto:rostedt@goodmis.org
122 2. tz.stoyanov@gmail.com
124 mailto:tz.stoyanov@gmail.com
125 3. linux-trace-devel@vger.kernel.org
127 mailto:linux-trace-devel@vger.kernel.org
128libtraceevent 1.5.3 04/15/2022 LIBTRACEEVENT(3)