Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755039AbaJWQr2 (ORCPT ); Thu, 23 Oct 2014 12:47:28 -0400 Received: from mail-yh0-f46.google.com ([209.85.213.46]:62797 "EHLO mail-yh0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751764AbaJWQr1 (ORCPT ); Thu, 23 Oct 2014 12:47:27 -0400 Date: Thu, 23 Oct 2014 12:47:23 -0400 (EDT) From: Nicolas Pitre To: Daniel Lezcano cc: rjw@rjwysocki.net, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, peterz@infradead.org, linaro-kernel@lists.linaro.org, patches@linaro.org Subject: Re: [PATCH V2 5/5] cpuidle: menu: Move the update function before its declaration In-Reply-To: <1414054881-17713-5-git-send-email-daniel.lezcano@linaro.org> Message-ID: References: <1414054881-17713-1-git-send-email-daniel.lezcano@linaro.org> <1414054881-17713-5-git-send-email-daniel.lezcano@linaro.org> User-Agent: Alpine 2.11 (LFD 23 2013-08-11) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 23 Oct 2014, Daniel Lezcano wrote: > In order to prevent a pointless forward declaration, just move the function > at the beginning of the file. > > This patch does not change the behavior of the governor, it is just code > reordering. > > Signed-off-by: Daniel Lezcano Acked-by: Nicolas Pitre > --- > drivers/cpuidle/governors/menu.c | 149 +++++++++++++++++++-------------------- > 1 file changed, 74 insertions(+), 75 deletions(-) > > diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c > index 6ae8390..0ac76b1 100644 > --- a/drivers/cpuidle/governors/menu.c > +++ b/drivers/cpuidle/governors/menu.c > @@ -184,7 +184,6 @@ static inline int performance_multiplier(unsigned long nr_iowaiters, unsigned lo > > static DEFINE_PER_CPU(struct menu_device, menu_devices); > > -static void menu_update(struct cpuidle_driver *drv, struct cpuidle_device *dev); > > /* This implements DIV_ROUND_CLOSEST but avoids 64 bit division */ > static u64 div_round64(u64 dividend, u32 divisor) > @@ -192,6 +191,80 @@ static u64 div_round64(u64 dividend, u32 divisor) > return div_u64(dividend + (divisor / 2), divisor); > } > > +/** > + * menu_update - attempts to guess what happened after entry > + * @drv: cpuidle driver containing state data > + * @dev: the CPU > + */ > +static void menu_update(struct cpuidle_driver *drv, struct cpuidle_device *dev) > +{ > + struct menu_device *data = &__get_cpu_var(menu_devices); > + int last_idx = data->last_state_idx; > + struct cpuidle_state *target = &drv->states[last_idx]; > + unsigned int measured_us; > + unsigned int new_factor; > + > + /* > + * Try to figure out how much time passed between entry to low > + * power state and occurrence of the wakeup event. > + * > + * If the entered idle state didn't support residency measurements, > + * we are basically lost in the dark how much time passed. > + * As a compromise, assume we slept for the whole expected time. > + * > + * Any measured amount of time will include the exit latency. > + * Since we are interested in when the wakeup begun, not when it > + * was completed, we must subtract the exit latency. However, if > + * the measured amount of time is less than the exit latency, > + * assume the state was never reached and the exit latency is 0. > + */ > + if (unlikely(!(target->flags & CPUIDLE_FLAG_TIME_VALID))) { > + /* Use timer value as is */ > + measured_us = data->next_timer_us; > + > + } else { > + /* Use measured value */ > + measured_us = cpuidle_get_last_residency(dev); > + > + /* Deduct exit latency */ > + if (measured_us > target->exit_latency) > + measured_us -= target->exit_latency; > + > + /* Make sure our coefficients do not exceed unity */ > + if (measured_us > data->next_timer_us) > + measured_us = data->next_timer_us; > + } > + > + /* Update our correction ratio */ > + new_factor = data->correction_factor[data->bucket]; > + new_factor -= new_factor / DECAY; > + > + if (data->next_timer_us > 0 && measured_us < MAX_INTERESTING) > + new_factor += RESOLUTION * measured_us / data->next_timer_us; > + else > + /* > + * we were idle so long that we count it as a perfect > + * prediction > + */ > + new_factor += RESOLUTION; > + > + /* > + * We don't want 0 as factor; we always want at least > + * a tiny bit of estimated time. Fortunately, due to rounding, > + * new_factor will stay nonzero regardless of measured_us values > + * and the compiler can eliminate this test as long as DECAY > 1. > + */ > + if (DECAY == 1 && unlikely(new_factor == 0)) > + new_factor = 1; > + > + data->correction_factor[data->bucket] = new_factor; > + > + /* update the repeating-pattern data */ > + data->intervals[data->interval_ptr++] = measured_us; > + if (data->interval_ptr >= INTERVALS) > + data->interval_ptr = 0; > +} > + > /* > * Try detecting repeating patterns by keeping track of the last 8 > * intervals, and checking if the standard deviation of that set > @@ -378,80 +451,6 @@ static void menu_reflect(struct cpuidle_device *dev, int index) > } > > /** > - * menu_update - attempts to guess what happened after entry > - * @drv: cpuidle driver containing state data > - * @dev: the CPU > - */ > -static void menu_update(struct cpuidle_driver *drv, struct cpuidle_device *dev) > -{ > - struct menu_device *data = &__get_cpu_var(menu_devices); > - int last_idx = data->last_state_idx; > - struct cpuidle_state *target = &drv->states[last_idx]; > - unsigned int measured_us; > - unsigned int new_factor; > - > - /* > - * Try to figure out how much time passed between entry to low > - * power state and occurrence of the wakeup event. > - * > - * If the entered idle state didn't support residency measurements, > - * we are basically lost in the dark how much time passed. > - * As a compromise, assume we slept for the whole expected time. > - * > - * Any measured amount of time will include the exit latency. > - * Since we are interested in when the wakeup begun, not when it > - * was completed, we must subtract the exit latency. However, if > - * the measured amount of time is less than the exit latency, > - * assume the state was never reached and the exit latency is 0. > - */ > - if (unlikely(!(target->flags & CPUIDLE_FLAG_TIME_VALID))) { > - /* Use timer value as is */ > - measured_us = data->next_timer_us; > - > - } else { > - /* Use measured value */ > - measured_us = cpuidle_get_last_residency(dev); > - > - /* Deduct exit latency */ > - if (measured_us > target->exit_latency) > - measured_us -= target->exit_latency; > - > - /* Make sure our coefficients do not exceed unity */ > - if (measured_us > data->next_timer_us) > - measured_us = data->next_timer_us; > - } > - > - /* Update our correction ratio */ > - new_factor = data->correction_factor[data->bucket]; > - new_factor -= new_factor / DECAY; > - > - if (data->next_timer_us > 0 && measured_us < MAX_INTERESTING) > - new_factor += RESOLUTION * measured_us / data->next_timer_us; > - else > - /* > - * we were idle so long that we count it as a perfect > - * prediction > - */ > - new_factor += RESOLUTION; > - > - /* > - * We don't want 0 as factor; we always want at least > - * a tiny bit of estimated time. Fortunately, due to rounding, > - * new_factor will stay nonzero regardless of measured_us values > - * and the compiler can eliminate this test as long as DECAY > 1. > - */ > - if (DECAY == 1 && unlikely(new_factor == 0)) > - new_factor = 1; > - > - data->correction_factor[data->bucket] = new_factor; > - > - /* update the repeating-pattern data */ > - data->intervals[data->interval_ptr++] = measured_us; > - if (data->interval_ptr >= INTERVALS) > - data->interval_ptr = 0; > -} > - > -/** > * menu_enable_device - scans a CPU's states and does setup > * @drv: cpuidle driver > * @dev: the CPU > -- > 1.9.1 > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/