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From: Ulf Hansson <ulf.hansson@linaro.org>
To: "Rafael J . Wysocki" <rjw@rjwysocki.net>,
	Sudeep Holla <sudeep.holla@arm.com>,
	Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Daniel Lezcano <daniel.lezcano@linaro.org>,
	linux-pm@vger.kernel.org
Cc: "Raju P . L . S . S . S . N" <rplsssn@codeaurora.org>,
	Stephen Boyd <sboyd@kernel.org>, Tony Lindgren <tony@atomide.com>,
	Kevin Hilman <khilman@kernel.org>,
	Lina Iyer <ilina@codeaurora.org>,
	Ulf Hansson <ulf.hansson@linaro.org>,
	Viresh Kumar <viresh.kumar@linaro.org>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	linux-arm-kernel@lists.infradead.org,
	linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
	Lina Iyer <lina.iyer@linaro.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Frederic Weisbecker <fweisbec@gmail.com>,
	Ingo Molnar <mingo@kernel.org>
Subject: [PATCH v10 03/27] timer: Export next wakeup time of a CPU
Date: Thu, 29 Nov 2018 18:46:36 +0100	[thread overview]
Message-ID: <20181129174700.16585-4-ulf.hansson@linaro.org> (raw)
In-Reply-To: <20181129174700.16585-1-ulf.hansson@linaro.org>

From: Lina Iyer <lina.iyer@linaro.org>

Knowing the sleep duration of CPUs, is known to be needed while selecting
the most energy efficient idle state for a CPU or a group of CPUs.

However, to be able to compute the sleep duration, we need to know at what
time the next expected wakeup is for the CPU. Therefore, let's export this
information via a new function, tick_nohz_get_next_wakeup(). Following
changes make use of it.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Lina Iyer <ilina@codeaurora.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
Co-developed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
---

Changes in v10:
	- Updated function header of tick_nohz_get_next_wakeup().

---
 include/linux/tick.h     |  8 ++++++++
 kernel/time/tick-sched.c | 13 +++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/include/linux/tick.h b/include/linux/tick.h
index 55388ab45fd4..e48f6b26b425 100644
--- a/include/linux/tick.h
+++ b/include/linux/tick.h
@@ -125,6 +125,7 @@ extern bool tick_nohz_idle_got_tick(void);
 extern ktime_t tick_nohz_get_sleep_length(ktime_t *delta_next);
 extern unsigned long tick_nohz_get_idle_calls(void);
 extern unsigned long tick_nohz_get_idle_calls_cpu(int cpu);
+extern ktime_t tick_nohz_get_next_wakeup(int cpu);
 extern u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time);
 extern u64 get_cpu_iowait_time_us(int cpu, u64 *last_update_time);
 
@@ -151,6 +152,13 @@ static inline ktime_t tick_nohz_get_sleep_length(ktime_t *delta_next)
 	*delta_next = TICK_NSEC;
 	return *delta_next;
 }
+
+static inline ktime_t tick_nohz_get_next_wakeup(int cpu)
+{
+	/* Next wake up is the tick period, assume it starts now */
+	return ktime_add(ktime_get(), TICK_NSEC);
+}
+
 static inline u64 get_cpu_idle_time_us(int cpu, u64 *unused) { return -1; }
 static inline u64 get_cpu_iowait_time_us(int cpu, u64 *unused) { return -1; }
 
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 69e673b88474..7a9166506503 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -1089,6 +1089,19 @@ unsigned long tick_nohz_get_idle_calls(void)
 	return ts->idle_calls;
 }
 
+/**
+ * tick_nohz_get_next_wakeup - return the next wake up of the CPU
+ * @cpu: the particular CPU to get next wake up for
+ *
+ * Called for idle CPUs only.
+ */
+ktime_t tick_nohz_get_next_wakeup(int cpu)
+{
+	struct clock_event_device *dev = per_cpu(tick_cpu_device.evtdev, cpu);
+
+	return dev->next_event;
+}
+
 static void tick_nohz_account_idle_ticks(struct tick_sched *ts)
 {
 #ifndef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
-- 
2.17.1


  parent reply	other threads:[~2018-11-29 17:47 UTC|newest]

Thread overview: 73+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-29 17:46 [PATCH v10 00/27] PM / Domains: Support hierarchical CPU arrangement (PSCI/ARM) Ulf Hansson
2018-11-29 17:46 ` [PATCH v10 01/27] PM / Domains: Add generic data pointer to genpd_power_state struct Ulf Hansson
2018-12-18 10:39   ` Daniel Lezcano
2018-12-18 11:53     ` Ulf Hansson
2019-01-11 10:52       ` Rafael J. Wysocki
2018-11-29 17:46 ` [PATCH v10 02/27] PM / Domains: Add support for CPU devices to genpd Ulf Hansson
2018-12-19  9:53   ` Daniel Lezcano
2018-12-19 10:02     ` Ulf Hansson
2019-01-11 10:54       ` Rafael J. Wysocki
2018-11-29 17:46 ` Ulf Hansson [this message]
2019-01-11 11:06   ` [PATCH v10 03/27] timer: Export next wakeup time of a CPU Rafael J. Wysocki
2019-01-16  7:57     ` Ulf Hansson
2019-01-16 10:59       ` Rafael J. Wysocki
2019-01-16 12:00         ` Ulf Hansson
2019-01-25 10:04           ` Ulf Hansson
2019-01-25 10:18             ` Rafael J. Wysocki
2018-11-29 17:46 ` [PATCH v10 04/27] PM / Domains: Add genpd governor for CPUs Ulf Hansson
2018-12-19  9:54   ` Daniel Lezcano
2018-12-19 10:09     ` Ulf Hansson
2018-11-29 17:46 ` [PATCH v10 05/27] dt: psci: Update DT bindings to support hierarchical PSCI states Ulf Hansson
2018-11-29 17:46 ` [PATCH v10 06/27] of: base: Add of_get_cpu_state_node() to get idle states for a CPU node Ulf Hansson
2018-12-19 11:05   ` Daniel Lezcano
2018-11-29 17:46 ` [PATCH v10 07/27] cpuidle: dt: Support hierarchical CPU idle states Ulf Hansson
2018-12-19 11:20   ` Daniel Lezcano
2018-11-29 17:46 ` [PATCH v10 08/27] ARM/ARM64: cpuidle: Let back-end init ops take the driver as input Ulf Hansson
2018-11-29 17:46 ` [PATCH v10 09/27] drivers: firmware: psci: Move psci to separate directory Ulf Hansson
2018-11-29 17:46 ` [PATCH v10 10/27] MAINTAINERS: Update files for PSCI Ulf Hansson
2018-11-29 17:46 ` [PATCH v10 11/27] drivers: firmware: psci: Split psci_dt_cpu_init_idle() Ulf Hansson
2018-11-29 17:46 ` [PATCH v10 12/27] drivers: firmware: psci: Simplify state node parsing Ulf Hansson
2018-11-29 17:46 ` [PATCH v10 13/27] drivers: firmware: psci: Support hierarchical CPU idle states Ulf Hansson
2018-12-19 12:11   ` Daniel Lezcano
2018-12-19 12:53     ` Ulf Hansson
2018-11-29 17:46 ` [PATCH v10 14/27] drivers: firmware: psci: Simplify error path of psci_dt_init() Ulf Hansson
2018-12-19 12:08   ` Daniel Lezcano
2018-11-29 17:46 ` [PATCH v10 15/27] drivers: firmware: psci: Announce support for OS initiated suspend mode Ulf Hansson
2018-12-20 13:11   ` Daniel Lezcano
2018-11-29 17:46 ` [PATCH v10 16/27] drivers: firmware: psci: Prepare to use " Ulf Hansson
2018-12-20 14:08   ` Daniel Lezcano
2018-12-20 15:41     ` Ulf Hansson
2018-12-20 17:16       ` Daniel Lezcano
2018-11-29 17:46 ` [PATCH v10 17/27] drivers: firmware: psci: Prepare to support PM domains Ulf Hansson
2018-12-20 14:19   ` Daniel Lezcano
2018-12-20 15:49     ` Ulf Hansson
2018-12-20 18:06       ` Daniel Lezcano
2018-12-20 21:37         ` Ulf Hansson
2018-12-21  7:15           ` Daniel Lezcano
2018-11-29 17:46 ` [PATCH v10 18/27] drivers: firmware: psci: Add support for PM domains using genpd Ulf Hansson
2018-12-03 16:37   ` Lina Iyer
2018-12-03 20:03     ` Ulf Hansson
2018-12-20 14:35   ` Daniel Lezcano
2018-12-20 21:09     ` Ulf Hansson
2018-11-29 17:46 ` [PATCH v10 19/27] drivers: firmware: psci: Add hierarchical domain idle states converter Ulf Hansson
2018-11-29 17:46 ` [PATCH v10 20/27] drivers: firmware: psci: Introduce psci_dt_topology_init() Ulf Hansson
2018-11-29 17:46 ` [PATCH v10 21/27] drivers: firmware: psci: Add a helper to attach a CPU to its PM domain Ulf Hansson
2018-12-04 18:45   ` Lina Iyer
2018-12-06  9:15     ` Ulf Hansson
2018-11-29 17:46 ` [PATCH v10 22/27] drivers: firmware: psci: Attach the CPU's device " Ulf Hansson
2018-11-29 17:46 ` [PATCH v10 23/27] drivers: firmware: psci: Manage runtime PM in the idle path for CPUs Ulf Hansson
2018-11-29 17:46 ` [PATCH v10 24/27] drivers: firmware: psci: Support CPU hotplug for the hierarchical model Ulf Hansson
2018-11-29 22:31   ` Lina Iyer
2018-11-30  8:25     ` Ulf Hansson
2018-11-30 20:57       ` Lina Iyer
2018-12-19 11:17   ` Lorenzo Pieralisi
2018-12-19 11:47     ` Ulf Hansson
2018-11-29 17:46 ` [PATCH v10 25/27] arm64: kernel: Respect the hierarchical CPU topology in DT for PSCI Ulf Hansson
2018-11-29 17:46 ` [PATCH v10 26/27] arm64: dts: Convert to the hierarchical CPU topology layout for MSM8916 Ulf Hansson
2018-11-29 17:47 ` [PATCH v10 27/27] arm64: dts: hikey: Convert to the hierarchical CPU topology layout Ulf Hansson
2018-12-17 16:12 ` [PATCH v10 00/27] PM / Domains: Support hierarchical CPU arrangement (PSCI/ARM) Ulf Hansson
2019-01-11 11:08   ` Rafael J. Wysocki
2019-01-03 12:06 ` Sudeep Holla
2019-01-16  9:10   ` Ulf Hansson
2019-01-17 17:44     ` Sudeep Holla
2019-01-18 11:56       ` Ulf Hansson

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