Commit 56534673 authored by Ionut Nechita (Sunlight Linux)'s avatar Ionut Nechita (Sunlight Linux) Committed by Thomas Gleixner
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tick/nohz: Optimize check_tick_dependency() with early return 



There is no point in iterating through individual tick dependency bits when
the tick_stop tracepoint is disabled, which is the common case.

When the trace point is disabled, return immediately based on the atomic
value being zero or non-zero, skipping the per-bit evaluation.

This optimization improves the hot path performance of tick dependency
checks across all contexts (idle and non-idle), not just nohz_full CPUs.

Suggested-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarIonut Nechita (Sunlight Linux) <sunlightlinux@gmail.com>
Signed-off-by: default avatarThomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260128074558.15433-3-sunlightlinux@gmail.com
parent 3db5306b

kernel/time/tick-sched.c

+3 −0
Original line number Diff line number Diff line
@@ -344,6 +344,9 @@ static bool check_tick_dependency(atomic_t *dep) 
{

	int val = atomic_read(dep);



	if (likely(!tracepoint_enabled(tick_stop)))

		return !val;



	if (val & TICK_DEP_MASK_POSIX_TIMER) {

		trace_tick_stop(0, TICK_DEP_MASK_POSIX_TIMER);

		return true;