From fcbd7897b871e157ee5c595e950c8466d86c0cd5 Mon Sep 17 00:00:00 2001 From: Breno Leitao Date: Mon, 5 Jan 2026 06:37:06 -0800 Subject: [PATCH] cpuidle: menu: Remove incorrect unlikely() annotation 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 Link: https://patch.msgid.link/20260105-annotated_idle-v1-1-10ddf0771b58@debian.org Signed-off-by: Rafael J. Wysocki --- drivers/cpuidle/governors/menu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c index 64d6f7a1c7766..ef9c5a84643ee 100644 --- a/drivers/cpuidle/governors/menu.c +++ b/drivers/cpuidle/governors/menu.c @@ -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)) { -- 2.47.3