From: Peter Zijlstra <peterz@infradead.org>
To: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>,
Linux PM <linux-pm@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Daniel Lezcano <daniel.lezcano@linaro.org>
Subject: Re: [PATCH 3/6] cpuidle: menu: Get rid of first_idx from menu_select()
Date: Thu, 4 Oct 2018 10:00:06 +0200 [thread overview]
Message-ID: <20181004080006.GH19272@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <CAJZ5v0gvAOz7R8uwXy=37ni=+dz9-gb69S2M2PtZSXc+tUhxrQ@mail.gmail.com>
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@infradead.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!
next prev parent reply other threads:[~2018-10-04 8:00 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-02 21:41 [PATCH 0/6] cpuidle: menu: Fixes, optimizations and cleanups Rafael J. Wysocki
2018-10-02 21:42 ` [PATCH 1/6] cpuidle: menu: Fix wakeup statistics updates for polling state Rafael J. Wysocki
2018-10-04 8:19 ` Daniel Lezcano
2018-10-02 21:42 ` [PATCH 2/6] cpuidle: menu: Compute first_idx when latency_req is known Rafael J. Wysocki
2018-10-04 14:22 ` Daniel Lezcano
2018-10-02 21:44 ` [PATCH 3/6] cpuidle: menu: Get rid of first_idx from menu_select() Rafael J. Wysocki
2018-10-04 7:46 ` Peter Zijlstra
2018-10-04 7:53 ` Rafael J. Wysocki
2018-10-04 8:00 ` Peter Zijlstra [this message]
2018-10-04 14:51 ` Daniel Lezcano
2018-10-04 17:19 ` Rafael J. Wysocki
2018-10-05 8:35 ` Daniel Lezcano
2018-10-05 8:49 ` Rafael J. Wysocki
2018-10-02 21:45 ` [PATCH 4/6] cpuidle: menu: Do not update last_state_idx in menu_select() Rafael J. Wysocki
2018-10-04 14:57 ` Daniel Lezcano
2018-10-02 21:46 ` [PATCH 5/6] cpuidle: menu: Avoid computations for very close timers Rafael J. Wysocki
2018-10-04 15:50 ` Daniel Lezcano
2018-10-04 17:11 ` Rafael J. Wysocki
2018-10-02 21:47 ` [PATCH 6/6] cpuidle: menu: Move the latency_req == 0 special case check Rafael J. Wysocki
2018-10-04 6:55 ` [PATCH 0/6] cpuidle: menu: Fixes, optimizations and cleanups Rafael J. Wysocki
2018-10-04 7:51 ` Peter Zijlstra
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