diff options
| author | Anna-Maria Behnsen <anna-maria@linutronix.de> | 2023-12-01 10:26:27 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2023-12-20 16:49:38 +0100 |
| commit | b573c73101d8786446535b2ab28cbc8907bda9a9 (patch) | |
| tree | e140e5e762cd980d96d58917cd4f89bde21303e1 | |
| parent | dbcdcb62b59db2cf6a24113873b90da15c6f0b19 (diff) | |
tracing/timers: Add tracepoint for tracking timer base is_idle flag
When debugging timer code the timer tracepoints are very important. There
is no tracepoint when the is_idle flag of the timer base changes. Instead
of always adding manually trace_printk(), add tracepoints which can be
easily enabled whenever required.
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20231201092654.34614-6-anna-maria@linutronix.de
| -rw-r--r-- | include/trace/events/timer.h | 20 | ||||
| -rw-r--r-- | kernel/time/timer.c | 14 |
2 files changed, 31 insertions, 3 deletions
diff --git a/include/trace/events/timer.h b/include/trace/events/timer.h index 99ada928d445..1ef58a04fc57 100644 --- a/include/trace/events/timer.h +++ b/include/trace/events/timer.h @@ -142,6 +142,26 @@ DEFINE_EVENT(timer_class, timer_cancel, TP_ARGS(timer) ); +TRACE_EVENT(timer_base_idle, + + TP_PROTO(bool is_idle, unsigned int cpu), + + TP_ARGS(is_idle, cpu), + + TP_STRUCT__entry( + __field( bool, is_idle ) + __field( unsigned int, cpu ) + ), + + TP_fast_assign( + __entry->is_idle = is_idle; + __entry->cpu = cpu; + ), + + TP_printk("is_idle=%d cpu=%d", + __entry->is_idle, __entry->cpu) +); + #define decode_clockid(type) \ __print_symbolic(type, \ { CLOCK_REALTIME, "CLOCK_REALTIME" }, \ diff --git a/kernel/time/timer.c b/kernel/time/timer.c index a81d793a43d0..ed8d6063d9ef 100644 --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -1950,7 +1950,10 @@ u64 get_next_timer_interrupt(unsigned long basej, u64 basem) if (time_before_eq(nextevt, basej)) { expires = basem; - base->is_idle = false; + if (base->is_idle) { + base->is_idle = false; + trace_timer_base_idle(false, base->cpu); + } } else { if (base->timers_pending) expires = basem + (u64)(nextevt - basej) * TICK_NSEC; @@ -1961,8 +1964,10 @@ u64 get_next_timer_interrupt(unsigned long basej, u64 basem) * logic is only maintained for the BASE_STD base, deferrable * timers may still see large granularity skew (by design). */ - if ((expires - basem) > TICK_NSEC) + if ((expires - basem) > TICK_NSEC && !base->is_idle) { base->is_idle = true; + trace_timer_base_idle(true, base->cpu); + } } raw_spin_unlock(&base->lock); @@ -1984,7 +1989,10 @@ void timer_clear_idle(void) * sending the IPI a few instructions smaller for the cost of taking * the lock in the exit from idle path. */ - base->is_idle = false; + if (base->is_idle) { + base->is_idle = false; + trace_timer_base_idle(false, smp_processor_id()); + } } #endif |