Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752800AbdI3HVf (ORCPT ); Sat, 30 Sep 2017 03:21:35 -0400 Received: from mga01.intel.com ([192.55.52.88]:36037 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752767AbdI3HVc (ORCPT ); Sat, 30 Sep 2017 03:21:32 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.42,456,1500966000"; d="scan'208";a="1020089288" From: Aubrey Li To: tglx@linutronix.de, peterz@infradead.org, rjw@rjwysocki.net, len.brown@intel.com, ak@linux.intel.com, tim.c.chen@linux.intel.com Cc: x86@kernel.org, linux-kernel@vger.kernel.org, Aubrey Li , Aubrey Li Subject: [RFC PATCH v2 1/8] cpuidle: menu: extract prediction functionality Date: Sat, 30 Sep 2017 15:20:27 +0800 Message-Id: <1506756034-6340-2-git-send-email-aubrey.li@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1506756034-6340-1-git-send-email-aubrey.li@intel.com> References: <1506756034-6340-1-git-send-email-aubrey.li@intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3828 Lines: 113 There are several factors in the menu governor to predict the next idle interval: - the next timer - the recent idle interval history - the corrected idle interval pattern These factors are common enough to be extracted to be one function. Signed-off-by: Aubrey Li --- drivers/cpuidle/governors/menu.c | 64 +++++++++++++++++++++++++--------------- 1 file changed, 40 insertions(+), 24 deletions(-) diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c index 61b64c2..6bed197 100644 --- a/drivers/cpuidle/governors/menu.c +++ b/drivers/cpuidle/governors/menu.c @@ -276,6 +276,45 @@ static unsigned int get_typical_interval(struct menu_device *data) } /** + * menu_predict - predict the coming idle interval + * + * Return the predicted coming idle interval in micro-second + */ +static unsigned int menu_predict(void) +{ + struct menu_device *data = this_cpu_ptr(&menu_devices); + unsigned int expected_interval; + int cpu = smp_processor_id(); + + if (!data) + return UINT_MAX; + + /* determine the expected residency time, round up */ + data->next_timer_us = ktime_to_us(tick_nohz_get_sleep_length()); + + data->bucket = which_bucket(data->next_timer_us, nr_iowait_cpu(cpu)); + + /* + * Force the result of multiplication to be 64 bits even if both + * operands are 32 bits. + * Make sure to round up for half microseconds. + */ + data->predicted_us = DIV_ROUND_CLOSEST_ULL((uint64_t) + data->next_timer_us * data->correction_factor[data->bucket], + RESOLUTION * DECAY); + + expected_interval = get_typical_interval(data); + expected_interval = min(expected_interval, data->next_timer_us); + + /* + * Use the lowest expected idle interval to pick the idle state. + */ + data->predicted_us = min(data->predicted_us, expected_interval); + + return data->predicted_us; +} + +/** * menu_select - selects the next idle state to enter * @drv: cpuidle driver containing state data * @dev: the CPU @@ -289,7 +328,6 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev) int first_idx; int idx; unsigned int interactivity_req; - unsigned int expected_interval; unsigned long nr_iowaiters, cpu_load; int resume_latency = dev_pm_qos_raw_read_value(device); @@ -306,24 +344,6 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev) if (unlikely(latency_req == 0)) return 0; - /* determine the expected residency time, round up */ - data->next_timer_us = ktime_to_us(tick_nohz_get_sleep_length()); - - get_iowait_load(&nr_iowaiters, &cpu_load); - data->bucket = which_bucket(data->next_timer_us, nr_iowaiters); - - /* - * Force the result of multiplication to be 64 bits even if both - * operands are 32 bits. - * Make sure to round up for half microseconds. - */ - data->predicted_us = DIV_ROUND_CLOSEST_ULL((uint64_t)data->next_timer_us * - data->correction_factor[data->bucket], - RESOLUTION * DECAY); - - expected_interval = get_typical_interval(data); - expected_interval = min(expected_interval, data->next_timer_us); - if (CPUIDLE_DRIVER_STATE_START > 0) { struct cpuidle_state *s = &drv->states[CPUIDLE_DRIVER_STATE_START]; unsigned int polling_threshold; @@ -345,14 +365,10 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev) } /* - * Use the lowest expected idle interval to pick the idle state. - */ - data->predicted_us = min(data->predicted_us, expected_interval); - - /* * Use the performance multiplier and the user-configurable * latency_req to determine the maximum exit latency. */ + get_iowait_load(&nr_iowaiters, &cpu_load); interactivity_req = data->predicted_us / performance_multiplier(nr_iowaiters, cpu_load); if (latency_req > interactivity_req) latency_req = interactivity_req; -- 2.7.4