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Date: Thu, 4 Oct 2018 10:00:06 +0200 From: Peter Zijlstra <peterz@...radead.org> To: "Rafael J. Wysocki" <rafael@...nel.org> Cc: "Rafael J. Wysocki" <rjw@...ysocki.net>, Linux PM <linux-pm@...r.kernel.org>, Linux Kernel Mailing List <linux-kernel@...r.kernel.org>, Daniel Lezcano <daniel.lezcano@...aro.org> Subject: Re: [PATCH 3/6] cpuidle: menu: Get rid of first_idx from menu_select() On Thu, Oct 04, 2018 at 09:53:39AM +0200, Rafael J. Wysocki wrote: > On Thu, Oct 4, 2018 at 9:46 AM Peter Zijlstra <peterz@...radead.org> wrote: > > > > On Tue, Oct 02, 2018 at 11:44:06PM +0200, Rafael J. Wysocki wrote: > > > idx = -1; > > > - for (i = first_idx; i < drv->state_count; i++) { > > > + for (i = 0; i < drv->state_count; i++) { > > > struct cpuidle_state *s = &drv->states[i]; > > > struct cpuidle_state_usage *su = &dev->states_usage[i]; > > > > > > if (s->disabled || su->disable) > > > continue; > > > + > > > if (idx == -1) > > > idx = i; /* first enabled state */ > > > + > > > if (s->target_residency > predicted_us) { > > > + /* > > > + * Use a physical idle state, not busy polling, unless > > > + * a timer is going to trigger really really soon. > > > + */ > > > + if ((drv->states[idx].flags & CPUIDLE_FLAG_POLLING) && > > > + i == idx + 1 && latency_req > s->exit_latency && > > > + data->next_timer_us > max_t(unsigned int, 20, > > > + s->target_residency)) { > > > > Not new in this patch, but this is where I really noticed it; that 20, > > should that not be something like: POLL_IDLE_TIME_LIMIT / NSEC_PER_USEC > > ? > > The POLL_IDLE_TIME_LIMIT is how much time we allow it to spin in > idle_poll() and I'm not sure it is related. Besides, I want it to go > away actually (https://patchwork.kernel.org/patch/10624117/). Ah, ok. Making it go away is better still!
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