diff mbox series

[RFC,v4,7/7] libtraceevent: prefer to use prev_state_char introduced in sched_switch

Message ID 20230802121116.324604-8-zegao@tencent.com
State New
Headers
Series fix task state report from sched tracepoint |

Commit Message

Ze Gao Aug. 2, 2023, 12:10 p.m. UTC 
  Since the sched_switch tracepoint introduces a new variable to
report sched-out task state in symbolic char, we prefer to use
it to spare from knowing internal implementations in kernel.

Also we keep the old parsing logic intact but sync the state char
array with the latest kernel.

Signed-off-by: Ze Gao <zegao@tencent.com>
---
 plugins/plugin_sched_switch.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

Comments

Steven Rostedt Aug. 2, 2023, 3:08 p.m. UTC | #1 
On Wed,  2 Aug 2023 08:10:02 -0400
Ze Gao <zegao2021@gmail.com> wrote:

> Since the sched_switch tracepoint introduces a new variable to
> report sched-out task state in symbolic char, we prefer to use
> it to spare from knowing internal implementations in kernel.
> 
> Also we keep the old parsing logic intact but sync the state char
> array with the latest kernel.
> 

This should also go to linux-trace-devel@vger.kernel.org.

> Signed-off-by: Ze Gao <zegao@tencent.com>
> ---
>  plugins/plugin_sched_switch.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/plugins/plugin_sched_switch.c b/plugins/plugin_sched_switch.c
> index e0986ac..4c57322 100644
> --- a/plugins/plugin_sched_switch.c
> +++ b/plugins/plugin_sched_switch.c
> @@ -11,7 +11,7 @@
>  
>  static void write_state(struct trace_seq *s, int val)
>  {
> -	const char states[] = "SDTtXZPI";
> +	const char states[] = "SDTtXZPIp";
>  	int found = 0;
>  	int i;
>  
> @@ -99,7 +99,12 @@ static int sched_switch_handler(struct trace_seq *s,
>  	if (tep_get_field_val(s, event, "prev_prio", record, &val, 1) == 0)
>  		trace_seq_printf(s, "[%d] ", (int) val);
>  
> -	if (tep_get_field_val(s,  event, "prev_state", record, &val, 1) == 0)
> +	//find if has prev_state_char, otherwise fallback to prev_state

Use standard C comment notation "/* ... */"

> +	if (tep_find_field(event, "prev_state_char")) {
> +		if (tep_get_field_val(s,  event, "prev_state_char", record, &val, 1) == 0)
> +			trace_seq_putc(s, (char) val);
> +	}
> +	else if (tep_get_field_val(s,  event, "prev_state", record, &val, 1) == 0)

This should be:

	} else if (..) {

>  		write_state(s, val);

	}

-- Steve

>  
>  	trace_seq_puts(s, " ==> ");
diff mbox series

Patch

diff --git a/plugins/plugin_sched_switch.c b/plugins/plugin_sched_switch.c
index e0986ac..4c57322 100644
--- a/plugins/plugin_sched_switch.c
+++ b/plugins/plugin_sched_switch.c
@@ -11,7 +11,7 @@ 
 
 static void write_state(struct trace_seq *s, int val)
 {
-	const char states[] = "SDTtXZPI";
+	const char states[] = "SDTtXZPIp";
 	int found = 0;
 	int i;
 
@@ -99,7 +99,12 @@  static int sched_switch_handler(struct trace_seq *s,
 	if (tep_get_field_val(s, event, "prev_prio", record, &val, 1) == 0)
 		trace_seq_printf(s, "[%d] ", (int) val);
 
-	if (tep_get_field_val(s,  event, "prev_state", record, &val, 1) == 0)
+	//find if has prev_state_char, otherwise fallback to prev_state
+	if (tep_find_field(event, "prev_state_char")) {
+		if (tep_get_field_val(s,  event, "prev_state_char", record, &val, 1) == 0)
+			trace_seq_putc(s, (char) val);
+	}
+	else if (tep_get_field_val(s,  event, "prev_state", record, &val, 1) == 0)
 		write_state(s, val);
 
 	trace_seq_puts(s, " ==> ");