linux.git/include/trace/events/timer.h, branch v7.1-rc2

hrtimer: Drop unnecessary pointer indirection in hrtimer_expire_entry event

2026-03-12T11:15:55+00:00

This pointer indirection is a remnant from when ktime_t was a struct,
today it is pointless.

Drop the pointer indirection.

Signed-off-by: Thomas Weißschuh (Schneider Electric) 
Signed-off-by: Thomas Gleixner 
Link: https://patch.msgid.link/20260311-hrtimer-cleanups-v1-9-095357392669@linutronix.de

hrtimer: Add hrtimer_rearm tracepoint

2026-02-27T15:40:12+00:00

Analyzing the reprogramming of the clock event device is essential to debug
the behaviour of the hrtimer subsystem especially with the upcoming
deferred rearming scheme.

Signed-off-by: Thomas Gleixner 
Signed-off-by: Peter Zijlstra (Intel) 
Link: https://patch.msgid.link/20260224163430.803669745@kernel.org

hrtimer: Reduce trace noise in hrtimer_start()

2026-02-27T15:40:09+00:00

hrtimer_start() when invoked with an already armed timer traces like:

 -..   [032] d.h2. 5.002263: hrtimer_cancel: hrtimer= ....
 -..   [032] d.h1. 5.002263: hrtimer_start: hrtimer= ....

Which is incorrect as the timer doesn't get canceled. Just the expiry time
changes. The internal dequeue operation which is required for that is not
really interesting for trace analysis. But it makes it tedious to keep real
cancellations and the above case apart.

Remove the cancel tracing in hrtimer_start() and add a 'was_armed'
indicator to the hrtimer start tracepoint, which clearly indicates what the
state of the hrtimer is when hrtimer_start() is invoked:

-..   [032] d.h1. 6.200103: hrtimer_start: hrtimer= .... was_armed=0
 -..   [032] d.h1. 6.200558: hrtimer_start: hrtimer= .... was_armed=1

Fixes: c6a2a1770245 ("hrtimer: Add tracepoint for hrtimers")
Signed-off-by: Thomas Gleixner 
Signed-off-by: Peter Zijlstra (Intel) 
Link: https://patch.msgid.link/20260224163430.208491877@kernel.org

tracing/timers: Rename the hrtimer_init event to hrtimer_setup

2025-04-05T08:30:17+00:00

The function hrtimer_init() doesn't exist anymore. It was replaced by
hrtimer_setup().

Thus, rename the hrtimer_init trace event to hrtimer_setup to keep it
consistent.

Signed-off-by: Nam Cao 
Signed-off-by: Thomas Gleixner 
Signed-off-by: Ingo Molnar 
Link: https://lore.kernel.org/all/cba84c3d853c5258aa3a262363a6eac08e2c7afc.1738746927.git.namcao@linutronix.de

hrtimers: Make callback function pointer private

2025-04-05T08:30:17+00:00

Make the struct hrtimer::function field private, to prevent users from
changing this field in an unsafe way. hrtimer_update_function() should be
used if the callback function needs to be changed.

Signed-off-by: Nam Cao 
Signed-off-by: Thomas Gleixner 
Signed-off-by: Ingo Molnar 
Link: https://lore.kernel.org/all/7d0e6e0c5c59a64a9bea940051aac05d750bc0c2.1738746927.git.namcao@linutronix.de

tracing/timers: Add tracepoint for tracking timer base is_idle flag

2023-12-20T15:49:38+00:00

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 
Signed-off-by: Thomas Gleixner 
Reviewed-by: Frederic Weisbecker 
Link: https://lore.kernel.org/r/20231201092654.34614-6-anna-maria@linutronix.de

tracing/timers: Enhance timer_start tracepoint

2023-12-20T15:49:38+00:00

For starting a timer, the timer is enqueued into a bucket of the timer
wheel. The bucket expiry is the defacto expiry of the timer but it is not
equal the timer expiry because of increasing granularity when bucket is in
a higher level of the wheel. To be able to figure out in a trace whether a
timer expired in time or not, the bucket expiry time is required as well.

Add bucket expiry time to the timer_start tracepoint and thereby simplify
the arguments.

Signed-off-by: Anna-Maria Behnsen 
Signed-off-by: Thomas Gleixner 
Reviewed-by: Frederic Weisbecker 
Link: https://lore.kernel.org/r/20231201092654.34614-5-anna-maria@linutronix.de

tracing/timer: Add missing hrtimer modes to decode_hrtimer_mode().

2023-06-19T07:09:14+00:00

The trace output for the HRTIMER_MODE_.*_HARD modes is seen as a number
since these modes are not decoded. The author was not aware of the fancy
decoding function which makes the life easier.

Extend decode_hrtimer_mode() with the additional HRTIMER_MODE_.*_HARD
modes.

Fixes: ae6683d815895 ("hrtimer: Introduce HARD expiry mode")
Signed-off-by: Sebastian Andrzej Siewior 
Signed-off-by: Thomas Gleixner 
Reviewed-by: Mukesh Ojha 
Acked-by: Steven Rostedt (Google) 
Link: https://lore.kernel.org/r/20230418143854.8vHWQKLM@linutronix.de

rcu: Fix missing TICK_DEP_MASK_RCU_EXP dependency check

2023-04-05T13:47:43+00:00

This commit adds checks for the TICK_DEP_MASK_RCU_EXP bit, thus enabling
RCU expedited grace periods to actually force-enable scheduling-clock
interrupts on holdout CPUs.

Fixes: df1e849ae455 ("rcu: Enable tick for nohz_full CPUs slow to provide expedited QS")
Signed-off-by: Zqiang 
Cc: Steven Rostedt 
Cc: Masami Hiramatsu 
Cc: Frederic Weisbecker 
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: Anna-Maria Behnsen 
Acked-by: Frederic Weisbecker 
Signed-off-by: Paul E. McKenney 
Signed-off-by: Joel Fernandes (Google)

tracing/timer: Add missing argument documentation of trace points

2022-04-14T14:14:49+00:00

Documentation of trace points timer_start, timer_expire_entry and
hrtimer_start lack always the last argument. Add it to keep implementation
and documentation in sync.

Signed-off-by: Anna-Maria Behnsen 
Signed-off-by: Thomas Gleixner 
Acked-by: Steven Rostedt (Google) 
Link: https://lore.kernel.org/r/20220411140115.24185-1-anna-maria@linutronix.de