From 6a5f95b5a4f4ff29e4071bc5b95f8f3a2aef046b Mon Sep 17 00:00:00 2001 From: Fieah Lim Date: Tue, 11 Sep 2018 03:59:01 +0800 Subject: cpuidle: Remove unnecessary wrapper cpuidle_get_last_residency() cpuidle_get_last_residency() is just a wrapper for retrieving the last_residency member of struct cpuidle_device. It's also weirdly the only wrapper function for accessing cpuidle_* struct member (by my best guess is it could be a leftover from v2.x). Anyhow, since the only two users (the ladder and menu governors) can access dev->last_residency directly, and it's more intuitive to do it that way, let's just get rid of the wrapper. This patch tidies up CPU idle code a bit without functional changes. Signed-off-by: Fieah Lim [ rjw: Changelog cleanup ] Signed-off-by: Rafael J. Wysocki --- include/linux/cpuidle.h | 10 ---------- 1 file changed, 10 deletions(-) (limited to 'include') diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h index 4325d6fdde9b..d262f620890e 100644 --- a/include/linux/cpuidle.h +++ b/include/linux/cpuidle.h @@ -99,16 +99,6 @@ struct cpuidle_device { DECLARE_PER_CPU(struct cpuidle_device *, cpuidle_devices); DECLARE_PER_CPU(struct cpuidle_device, cpuidle_dev); -/** - * cpuidle_get_last_residency - retrieves the last state's residency time - * @dev: the target CPU - */ -static inline int cpuidle_get_last_residency(struct cpuidle_device *dev) -{ - return dev->last_residency; -} - - /**************************** * CPUIDLE DRIVER INTERFACE * ****************************/ -- cgit v1.2.3 From 5f26bdceb9c0a5e6c696aa2899d077cd3ae93413 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Tue, 2 Oct 2018 23:42:02 +0200 Subject: cpuidle: menu: Fix wakeup statistics updates for polling state If the CPU exits the "polling" state due to the time limit in the loop in poll_idle(), this is not a real wakeup and it just means that the "polling" state selection was not adequate. The governor mispredicted short idle duration, but had a more suitable state been selected, the CPU might have spent more time in it. In fact, there is no reason to expect that there would have been a wakeup event earlier than the next timer in that case. Handling such cases as regular wakeups in menu_update() may cause the menu governor to make suboptimal decisions going forward, but ignoring them altogether would not be correct either, because every time menu_select() is invoked, it makes a separate new attempt to predict the idle duration taking distinct time to the closest timer event as input and the outcomes of all those attempts should be recorded. For this reason, make menu_update() always assume that if the "polling" state was exited due to the time limit, the next proper wakeup event for the CPU would be the next timer event (not including the tick). Fixes: a37b969a61c1 "cpuidle: poll_state: Add time limit to poll_idle()" Signed-off-by: Rafael J. Wysocki Acked-by: Peter Zijlstra (Intel) Reviewed-by: Daniel Lezcano --- drivers/cpuidle/governors/menu.c | 10 ++++++++++ drivers/cpuidle/poll_state.c | 6 +++++- include/linux/cpuidle.h | 1 + 3 files changed, 16 insertions(+), 1 deletion(-) (limited to 'include') diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c index b6684fd89085..8b3f9c7bf221 100644 --- a/drivers/cpuidle/governors/menu.c +++ b/drivers/cpuidle/governors/menu.c @@ -511,6 +511,16 @@ static void menu_update(struct cpuidle_driver *drv, struct cpuidle_device *dev) * duration predictor do a better job next time. */ measured_us = 9 * MAX_INTERESTING / 10; + } else if ((drv->states[last_idx].flags & CPUIDLE_FLAG_POLLING) && + dev->poll_time_limit) { + /* + * The CPU exited the "polling" state due to a time limit, so + * the idle duration prediction leading to the selection of that + * state was inaccurate. If a better prediction had been made, + * the CPU might have been woken up from idle by the next timer. + * Assume that to be the case. + */ + measured_us = data->next_timer_us; } else { /* measured value */ measured_us = dev->last_residency; diff --git a/drivers/cpuidle/poll_state.c b/drivers/cpuidle/poll_state.c index 3f86d23c592e..36ff5a1d9422 100644 --- a/drivers/cpuidle/poll_state.c +++ b/drivers/cpuidle/poll_state.c @@ -17,6 +17,8 @@ static int __cpuidle poll_idle(struct cpuidle_device *dev, { u64 time_start = local_clock(); + dev->poll_time_limit = false; + local_irq_enable(); if (!current_set_polling_and_test()) { unsigned int loop_count = 0; @@ -27,8 +29,10 @@ static int __cpuidle poll_idle(struct cpuidle_device *dev, continue; loop_count = 0; - if (local_clock() - time_start > POLL_IDLE_TIME_LIMIT) + if (local_clock() - time_start > POLL_IDLE_TIME_LIMIT) { + dev->poll_time_limit = true; break; + } } } current_clr_polling(); diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h index d262f620890e..faed7a8977e8 100644 --- a/include/linux/cpuidle.h +++ b/include/linux/cpuidle.h @@ -81,6 +81,7 @@ struct cpuidle_device { unsigned int registered:1; unsigned int enabled:1; unsigned int use_deepest_state:1; + unsigned int poll_time_limit:1; unsigned int cpu; int last_residency; -- cgit v1.2.3