[PATCH] ftrace: add tgid information in task switch event.

[Jiejing Zhang <kzjeef@gmail.com>]

From: Jiejing Zhang <jiejzhang@nvidia.com>

ftrace only report pid in task switch event, which is
actually thread ID in user space view, the comm of
the thread will be like "Thread-1", "Compiler", etc
in android system, it's useful if we can add tgid
information in ftrace event to find out the process
id, and the process id's comm will help us to figure
out the application, which was useful on data analysis
tools.

Change-Id: Ia99f58a56d691d770b3beb2f76de0351e6194a4a
Signed-off-by: Jiejing Zhang <jiejzhang@nvidia.com>
---
 include/trace/events/sched.h | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h
index e5586ca..3fbcddb 100644
--- a/include/trace/events/sched.h
+++ b/include/trace/events/sched.h
@@ -124,32 +124,37 @@ TRACE_EVENT(sched_switch,
 	TP_STRUCT__entry(
 		__array(	char,	prev_comm,	TASK_COMM_LEN	)
 		__field(	pid_t,	prev_pid			)
+		__field(	pid_t,	prev_tgid			)
 		__field(	int,	prev_prio			)
 		__field(	long,	prev_state			)
 		__array(	char,	next_comm,	TASK_COMM_LEN	)
 		__field(	pid_t,	next_pid			)
+		__field(	pid_t,	next_tgid			)
 		__field(	int,	next_prio			)
 	),
 
 	TP_fast_assign(
 		memcpy(__entry->next_comm, next->comm, TASK_COMM_LEN);
 		__entry->prev_pid	= prev->pid;
+		__entry->prev_tgid	= prev->tgid;
 		__entry->prev_prio	= prev->prio;
 		__entry->prev_state	= __trace_sched_switch_state(prev);
 		memcpy(__entry->prev_comm, prev->comm, TASK_COMM_LEN);
 		__entry->next_pid	= next->pid;
+		__entry->next_tgid	= next->tgid;
 		__entry->next_prio	= next->prio;
 	),
 
-	TP_printk("prev_comm=%s prev_pid=%d prev_prio=%d prev_state=%s%s ==> next_comm=%s next_pid=%d next_prio=%d",
-		__entry->prev_comm, __entry->prev_pid, __entry->prev_prio,
+	TP_printk("prev_comm=%s prev_pid=%d prev_tgid=%d prev_prio=%d prev_state=%s%s ==> next_comm=%s next_pid=%d next_tgid=%d next_prio=%d",
+		__entry->prev_comm, __entry->prev_pid,
+		__entry->prev_tgid,  __entry->prev_prio,
 		__entry->prev_state & (TASK_STATE_MAX-1) ?
-		  __print_flags(__entry->prev_state & (TASK_STATE_MAX-1), "|",
+		__print_flags(__entry->prev_state & (TASK_STATE_MAX-1), "|",
 				{ 1, "S"} , { 2, "D" }, { 4, "T" }, { 8, "t" },
 				{ 16, "Z" }, { 32, "X" }, { 64, "x" },
 				{ 128, "K" }, { 256, "W" }, { 512, "P" }) : "R",
 		__entry->prev_state & TASK_STATE_MAX ? "+" : "",
-		__entry->next_comm, __entry->next_pid, __entry->next_prio)
+		__entry->next_comm, __entry->next_pid, __entry->next_tgid, __entry->next_prio)
 );
 
 /*
-- 
1.8.1.5