From: Breno Leitao Date: Mon, 5 Jan 2026 14:37:06 +0000 (-0800) Subject: cpuidle: menu: Remove incorrect unlikely() annotation X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=fcbd7897b871e157ee5c595e950c8466d86c0cd5;p=thirdparty%2Flinux.git 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 --- 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)) {