From f28d3d5346e97e60c81f933ac89ccf015430e5cf Mon Sep 17 00:00:00 2001 From: Anna-Maria Gleixner Date: Thu, 21 Mar 2019 13:09:21 +0100 Subject: timer/trace: Improve timer tracing Timers are added to the timer wheel off by one. This is required in case a timer is queued directly before incrementing jiffies to prevent early timer expiry. When reading a timer trace and relying only on the expiry time of the timer in the timer_start trace point and on the now in the timer_expiry_entry trace point, it seems that the timer fires late. With the current timer_expiry_entry trace point information only now=jiffies is printed but not the value of base->clk. This makes it impossible to draw a conclusion to the index of base->clk and makes it impossible to examine timer problems without additional trace points. Therefore add the base->clk value to the timer_expire_entry trace point, to be able to calculate the index the timer base is located at during collecting expired timers. Signed-off-by: Anna-Maria Gleixner Signed-off-by: Thomas Gleixner Cc: fweisbec@gmail.com Cc: peterz@infradead.org Cc: Steven Rostedt Link: https://lkml.kernel.org/r/20190321120921.16463-5-anna-maria@linutronix.de --- include/trace/events/timer.h | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) (limited to 'include') diff --git a/include/trace/events/timer.h b/include/trace/events/timer.h index da975d69c453..b7a904825e7d 100644 --- a/include/trace/events/timer.h +++ b/include/trace/events/timer.h @@ -89,24 +89,27 @@ TRACE_EVENT(timer_start, */ TRACE_EVENT(timer_expire_entry, - TP_PROTO(struct timer_list *timer), + TP_PROTO(struct timer_list *timer, unsigned long baseclk), - TP_ARGS(timer), + TP_ARGS(timer, baseclk), TP_STRUCT__entry( __field( void *, timer ) __field( unsigned long, now ) __field( void *, function) + __field( unsigned long, baseclk ) ), TP_fast_assign( __entry->timer = timer; __entry->now = jiffies; __entry->function = timer->function; + __entry->baseclk = baseclk; ), - TP_printk("timer=%p function=%ps now=%lu", - __entry->timer, __entry->function, __entry->now) + TP_printk("timer=%p function=%ps now=%lu baseclk=%lu", + __entry->timer, __entry->function, __entry->now, + __entry->baseclk) ); /** -- cgit v1.2.3