On Wed, Aug 2, 2023 at 11:05 PM Steven Rostedt [off-list ref] wrote:

On Wed,  2 Aug 2023 08:09:59 -0400
Ze Gao [off-list ref] wrote:

quoted

From: Ze Gao <redacted>

Report priorities in 'short' and prev_state in 'int' to save
some buffer space. And also reorder the fields so that we take
struct alignment into consideration to make the record compact.

Suggested-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Ze Gao <redacted>
---
 include/trace/events/sched.h | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h
index fbb99a61f714..7d34db20b2c6 100644
--- a/include/trace/events/sched.h
+++ b/include/trace/events/sched.h

@@ -187,7 +187,7 @@ DEFINE_EVENT(sched_wakeup_template, sched_wakeup_new,
           TP_ARGS(p));

 #ifdef CREATE_TRACE_POINTS
-static inline long __trace_sched_switch_state(bool preempt,
+static inline int __trace_sched_switch_state(bool preempt,
                                            unsigned int prev_state,
                                            struct task_struct *p)
 {

@@ -229,23 +229,23 @@ TRACE_EVENT(sched_switch,
      TP_ARGS(preempt, prev, next, prev_state),

      TP_STRUCT__entry(
-             __array(        char,   prev_comm,      TASK_COMM_LEN   )
              __field(        pid_t,  prev_pid                        )
-             __field(        int,    prev_prio                       )
-             __field(        long,   prev_state                      )
-             __array(        char,   next_comm,      TASK_COMM_LEN   )
              __field(        pid_t,  next_pid                        )
-             __field(        int,    next_prio                       )
+             __field(        short,  prev_prio                       )
+             __field(        short,  next_prio                       )
+             __field(        int,    prev_state                      )

I was talking with Peter on IRC and since the biggest number that
prev_state can be is TASK_REPORT_MASK which is 0x100, I think we can make
prev_state into a short as well.

Make sense, let's change it to short.

Regards,
Ze