[tip:perf/core] tools lib traceevent: Man pages for APIs used to extract common fields from a record

tip-bot for Tzvetomir Stoyanov
2019-05-18T09:18:03Z

Commit-ID: 0133fc6068fb51aa7ce8876e8fee465d92acfc14
Gitweb: https://git.kernel.org/tip/0133fc6068fb51aa7ce8876e8fee465d92acfc14
Author: Tzvetomir Stoyanov <tstoyanov@vmware.com>
AuthorDate: Fri, 10 May 2019 15:56:32 -0400
Committer: Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Wed, 15 May 2019 16:36:48 -0300

tools lib traceevent: Man pages for APIs used to extract common fields from a record

Create man pages for libtraceevent APIs:

tep_data_type(),
tep_data_pid(),
tep_data_preempt_count(),
tep_data_flags()

Signed-off-by: Tzvetomir Stoyanov <tstoyanov@vmware.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: linux-trace-devel@vger.kernel.org
Link: http://lore.kernel.org/linux-trace-devel/20190503091119.23399-26-tstoyanov@vmware.com
Link: http://lkml.kernel.org/r/20190510200110.284281830@goodmis.org
[ Fixed missing T in description of NOSUPPORT flag ]
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
.../Documentation/libtraceevent-record_parse.txt | 137 +++++++++++++++++++++
1 file changed, 137 insertions(+)

diff --git a/tools/lib/traceevent/Documentation/libtraceevent-record_parse.txt b/tools/lib/traceevent/Documentation/libtraceevent-record_parse.txt
new file mode 100644
index 000000000000..e9a69116c78b
--- /dev/null
+++ b/tools/lib/traceevent/Documentation/libtraceevent-record_parse.txt
@@ -0,0 +1,137 @@
+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 */