From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755294Ab3IYWiy (ORCPT ); Wed, 25 Sep 2013 18:38:54 -0400 Received: from mail-wi0-f180.google.com ([209.85.212.180]:33092 "EHLO mail-wi0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752941Ab3IYWix (ORCPT ); Wed, 25 Sep 2013 18:38:53 -0400 Message-ID: <524365FA.4090108@linaro.org> Date: Thu, 26 Sep 2013 00:38:50 +0200 From: Daniel Lezcano User-Agent: Mozilla/5.0 (X11; Linux i686; rv:24.0) Gecko/20100101 Thunderbird/24.0 MIME-Version: 1.0 To: Viresh Kumar , rjw@sisk.pl CC: linaro-kernel@lists.linaro.org, patches@linaro.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 20/21] cpuidle: don't calculate time-diff if entered_state == 0 References: In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/22/2013 03:21 AM, Viresh Kumar wrote: > If entered_state == 0, we don't need to set dev->last_residency to 'diff' as we > will be setting it to zero without using its new value. I don't get it, can you elaborate. We can be a long time in this state (eg. if the prediction is false). > And so move calculation of diff also inside the "if" statement. > Signed-off-by: Viresh Kumar > --- > drivers/cpuidle/cpuidle.c | 17 +++++++++-------- > 1 file changed, 9 insertions(+), 8 deletions(-) > > diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c > index bf80236..cb81689 100644 > --- a/drivers/cpuidle/cpuidle.c > +++ b/drivers/cpuidle/cpuidle.c > @@ -77,23 +77,22 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv, > > struct cpuidle_state *target_state = &drv->states[index]; > ktime_t time_start, time_end; > - s64 diff; > > time_start = ktime_get(); > > entered_state = target_state->enter(dev, drv, index); > > - time_end = ktime_get(); > + if (entered_state >= 0) { > + s64 diff; > > - local_irq_enable(); > + time_end = ktime_get(); > + diff = ktime_to_us(ktime_sub(time_end, time_start)); > > - diff = ktime_to_us(ktime_sub(time_end, time_start)); > - if (diff > INT_MAX) > - diff = INT_MAX; > + if (diff > INT_MAX) > + diff = INT_MAX; > > - dev->last_residency = (int) diff; > + dev->last_residency = (int) diff; > > - if (entered_state >= 0) { > /* Update cpuidle counters */ > /* This can be moved to within driver enter routine > * but that results in multiple copies of same code. > @@ -104,6 +103,8 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv, > dev->last_residency = 0; > } > > + local_irq_enable(); > + > return entered_state; > } > > -- Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog