From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Lezcano Subject: Re: [PATCH] cpuidle: Change ktime_get() with local_clock() Date: Wed, 20 Apr 2016 14:30:11 +0200 Message-ID: <20160420123011.GJ5862@linaro.org> References: <1460661834-5683-1-git-send-email-daniel.lezcano@linaro.org> <20160420121315.GC3408@twins.programming.kicks-ass.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-wm0-f53.google.com ([74.125.82.53]:37042 "EHLO mail-wm0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932105AbcDTMaR (ORCPT ); Wed, 20 Apr 2016 08:30:17 -0400 Received: by mail-wm0-f53.google.com with SMTP id n3so79160798wmn.0 for ; Wed, 20 Apr 2016 05:30:16 -0700 (PDT) Content-Disposition: inline In-Reply-To: <20160420121315.GC3408@twins.programming.kicks-ass.net> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: Peter Zijlstra Cc: rjw@rjwysocki.net, mingo@kernel.org, "open list:CPUIDLE DRIVERS" , open list On Wed, Apr 20, 2016 at 02:13:15PM +0200, Peter Zijlstra wrote: > On Thu, Apr 14, 2016 at 09:23:54PM +0200, Daniel Lezcano wrote: > > @@ -217,7 +217,11 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv, > > if (!cpuidle_state_is_coupled(drv, entered_state)) > > local_irq_enable(); > > > > - diff = ktime_to_us(ktime_sub(time_end, time_start)); > > + /* > > + * local_clock() returns the time in nanosecond, let's shift > > + * by 10 (divide by 1024) to have microsecond based time. > > + */ > > + diff = (time_end - time_start) >> 10; > > Changelog fails to explain the ramifications of this change... Sorry, I don't get the point of your comment. Do you mean I should elaborate the comment above in the changelog?