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cpuidle: menu: Remove incorrect unlikely() annotation

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The unlikely() annotation on the early-return condition in menu_select()
is incorrect on systems with only one idle state (e.g., ARM64 servers
with a single ACPI LPI state). Branch profiling shows 100% misprediction
on such systems since drv->state_count <= 1 is always true.

On platforms where only state0 is available, this path is the common
case, not an unlikely edge case. Remove the misleading annotation to
let the branch predictor learn the actual behavior.

Signed-off-by: Breno Leitao <leitao@debian.org>
Link: https://patch.msgid.link/20260105-annotated_idle-v1-1-10ddf0771b58@debian.org
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Breno Leitao 2026-01-05 06:37:06 -08:00 committed by Rafael J. Wysocki
parent be6a150829
commit fcbd7897b8
1 changed files with 1 additions and 1 deletions
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2
drivers/cpuidle/governors/menu.c
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@ -271,7 +271,7 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
data->bucket = BUCKETS - 1;
}
if (unlikely(drv->state_count <= 1 || latency_req == 0) ||
if (drv->state_count <= 1 || latency_req == 0 ||
((data->next_timer_ns < drv->states[1].target_residency_ns ||
latency_req < drv->states[1].exit_latency_ns) &&
!dev->states_usage[0].disable)) {