From: Lina Iyer <lina.iyer@linaro.org> To: ulf.hansson@linaro.org, khilman@kernel.org, rjw@rjwysocki.net, linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: andy.gross@linaro.org, sboyd@codeaurora.org, linux-arm-msm@vger.kernel.org, Lina Iyer <lina.iyer@linaro.org>, Thomas Gleixner <tglx@linutronix.de> Subject: [PATCH v3 08/15] timer: Export next wake up of a CPU Date: Thu, 4 Aug 2016 17:04:55 -0600 [thread overview] Message-ID: <1470351902-43103-9-git-send-email-lina.iyer@linaro.org> (raw) In-Reply-To: <1470351902-43103-1-git-send-email-lina.iyer@linaro.org> Knowing the sleep length of the CPU is useful for the power state determination on idle. The value is relative to the time when the call was invoked by the CPU. This doesn't work well when there is a need to know when the actual wakeup is. By reading the next wake up event of a CPU, governors can determine the first CPU to wake up (due to timer) amongst a cluster of CPUs and the sleep time available between the last CPU to idle and the first CPU to resume. This information is useful to determine if the caches and other common hardware blocks can also be put in idle during this common period of inactivity. Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Lina Iyer <lina.iyer@linaro.org> --- include/linux/tick.h | 7 +++++++ kernel/time/tick-sched.c | 11 +++++++++++ 2 files changed, 18 insertions(+) diff --git a/include/linux/tick.h b/include/linux/tick.h index 62be0786..92fa4b0 100644 --- a/include/linux/tick.h +++ b/include/linux/tick.h @@ -117,6 +117,7 @@ extern void tick_nohz_idle_enter(void); extern void tick_nohz_idle_exit(void); extern void tick_nohz_irq_exit(void); extern ktime_t tick_nohz_get_sleep_length(void); +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); #else /* !CONFIG_NO_HZ_COMMON */ @@ -131,6 +132,12 @@ static inline ktime_t tick_nohz_get_sleep_length(void) return len; } + +static inline ktime_t tick_nohz_get_next_wakeup(int cpu) +{ + return tick_next_period; +} + 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; } #endif /* !CONFIG_NO_HZ_COMMON */ diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 536ada8..5c7ac17 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -979,6 +979,17 @@ ktime_t tick_nohz_get_sleep_length(void) return ts->sleep_length; } +/** + * tick_nohz_get_next_wakeup - return the next wake up of the CPU + */ +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 -- 2.7.4
WARNING: multiple messages have this Message-ID (diff)
From: lina.iyer@linaro.org (Lina Iyer) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v3 08/15] timer: Export next wake up of a CPU Date: Thu, 4 Aug 2016 17:04:55 -0600 [thread overview] Message-ID: <1470351902-43103-9-git-send-email-lina.iyer@linaro.org> (raw) In-Reply-To: <1470351902-43103-1-git-send-email-lina.iyer@linaro.org> Knowing the sleep length of the CPU is useful for the power state determination on idle. The value is relative to the time when the call was invoked by the CPU. This doesn't work well when there is a need to know when the actual wakeup is. By reading the next wake up event of a CPU, governors can determine the first CPU to wake up (due to timer) amongst a cluster of CPUs and the sleep time available between the last CPU to idle and the first CPU to resume. This information is useful to determine if the caches and other common hardware blocks can also be put in idle during this common period of inactivity. Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Lina Iyer <lina.iyer@linaro.org> --- include/linux/tick.h | 7 +++++++ kernel/time/tick-sched.c | 11 +++++++++++ 2 files changed, 18 insertions(+) diff --git a/include/linux/tick.h b/include/linux/tick.h index 62be0786..92fa4b0 100644 --- a/include/linux/tick.h +++ b/include/linux/tick.h @@ -117,6 +117,7 @@ extern void tick_nohz_idle_enter(void); extern void tick_nohz_idle_exit(void); extern void tick_nohz_irq_exit(void); extern ktime_t tick_nohz_get_sleep_length(void); +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); #else /* !CONFIG_NO_HZ_COMMON */ @@ -131,6 +132,12 @@ static inline ktime_t tick_nohz_get_sleep_length(void) return len; } + +static inline ktime_t tick_nohz_get_next_wakeup(int cpu) +{ + return tick_next_period; +} + 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; } #endif /* !CONFIG_NO_HZ_COMMON */ diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 536ada8..5c7ac17 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -979,6 +979,17 @@ ktime_t tick_nohz_get_sleep_length(void) return ts->sleep_length; } +/** + * tick_nohz_get_next_wakeup - return the next wake up of the CPU + */ +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 -- 2.7.4
next prev parent reply other threads:[~2016-08-04 23:04 UTC|newest] Thread overview: 83+ messages / expand[flat|nested] mbox.gz Atom feed top 2016-08-04 23:04 [PATCH v3 00/15] PM: SoC idle support using PM domains Lina Iyer 2016-08-04 23:04 ` Lina Iyer 2016-08-04 23:04 ` [PATCH v3 01/15] PM / Domains: Allow domain power states to be read from DT Lina Iyer 2016-08-04 23:04 ` Lina Iyer 2016-08-04 23:04 ` [PATCH v3 02/15] dt/bindings: Update binding for PM domain idle states Lina Iyer 2016-08-04 23:04 ` Lina Iyer 2016-08-09 23:55 ` Rob Herring 2016-08-09 23:55 ` Rob Herring 2016-08-10 15:14 ` Sudeep Holla 2016-08-10 15:14 ` Sudeep Holla 2016-08-10 16:40 ` Lina Iyer 2016-08-10 16:40 ` Lina Iyer [not found] ` <20160810164034.GA1401-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org> 2016-08-10 18:09 ` Sudeep Holla 2016-08-10 18:09 ` Sudeep Holla 2016-08-10 18:13 ` Sudeep Holla 2016-08-10 18:13 ` Sudeep Holla [not found] ` <5e59874c-bbb7-270a-199c-da1ff5932554-5wv7dgnIgG8@public.gmane.org> 2016-08-11 21:10 ` Lina Iyer 2016-08-11 21:10 ` Lina Iyer [not found] ` <20160811211023.GC1401-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org> 2016-08-12 9:47 ` Brendan Jackman 2016-08-12 9:47 ` Brendan Jackman 2016-08-12 10:08 ` Sudeep Holla 2016-08-12 10:08 ` Sudeep Holla 2016-08-15 16:08 ` Lina Iyer 2016-08-15 16:08 ` Lina Iyer 2016-08-15 16:14 ` Sudeep Holla 2016-08-15 16:14 ` Sudeep Holla 2016-08-15 22:40 ` Lina Iyer 2016-08-15 22:40 ` Lina Iyer [not found] ` <20160815224014.GF1401-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org> 2016-08-16 8:34 ` Brendan Jackman 2016-08-16 8:34 ` Brendan Jackman 2016-08-16 8:41 ` Brendan Jackman 2016-08-16 8:41 ` Brendan Jackman 2016-08-16 9:19 ` Sudeep Holla 2016-08-16 9:19 ` Sudeep Holla 2016-08-12 12:35 ` Brendan Jackman 2016-08-12 12:35 ` Brendan Jackman 2016-08-15 16:06 ` Lina Iyer 2016-08-15 16:06 ` Lina Iyer 2016-08-19 18:10 ` Kevin Hilman 2016-08-19 18:10 ` Kevin Hilman 2016-08-24 14:07 ` Sudeep Holla 2016-08-24 14:07 ` Sudeep Holla [not found] ` <1470351902-43103-3-git-send-email-lina.iyer-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org> 2016-08-24 13:48 ` [RFC 0/6] Illustration of using domain-idle-states for CPU " Brendan Jackman 2016-08-24 13:48 ` [RFC 1/6] cpuidle: Rename cpuidle_get_{cpu->dev}_driver Brendan Jackman 2016-08-24 13:48 ` [RFC 2/6] cpuidle: Add public funcion to get driver from CPU index Brendan Jackman [not found] ` <20160824134822.3591-1-brendan.jackman-5wv7dgnIgG8@public.gmane.org> 2016-08-24 13:48 ` [RFC 3/6] cpuidle: Add device_node pointer in cpuidle_state Brendan Jackman 2016-08-24 13:48 ` [RFC 6/6] arm64: dts: Add domain-idle-states for Juno r0 power domains Brendan Jackman 2016-08-24 13:48 ` [RFC 4/6] cpuidle: dt: Add support for reading states from " Brendan Jackman 2016-08-24 13:48 ` [RFC 5/6] arm64: dts: Add Juno r0 CPU power domain tree Brendan Jackman 2016-08-04 23:04 ` [PATCH v3 03/15] PM / Domains: Abstract genpd locking Lina Iyer 2016-08-04 23:04 ` Lina Iyer 2016-08-04 23:04 ` [PATCH v3 04/15] PM / Domains: Support IRQ safe PM domains Lina Iyer 2016-08-04 23:04 ` Lina Iyer 2016-08-04 23:04 ` [PATCH v3 05/15] PM / doc: Update device documentation for devices in " Lina Iyer 2016-08-04 23:04 ` Lina Iyer 2016-08-04 23:04 ` [PATCH v3 06/15] PM / cpu_domains: Setup PM domains for CPUs/clusters Lina Iyer 2016-08-04 23:04 ` Lina Iyer 2016-08-04 23:04 ` [PATCH v3 07/15] ARM: cpuidle: Add runtime PM support for CPUs Lina Iyer 2016-08-04 23:04 ` Lina Iyer 2016-08-04 23:04 ` Lina Iyer [this message] 2016-08-04 23:04 ` [PATCH v3 08/15] timer: Export next wake up of a CPU Lina Iyer 2016-08-04 23:04 ` [PATCH v3 09/15] PM / cpu_domains: Add PM Domain governor for CPUs Lina Iyer 2016-08-04 23:04 ` Lina Iyer 2016-08-04 23:04 ` [PATCH v3 10/15] doc / cpu_domains: Describe CPU PM domains setup and governor Lina Iyer 2016-08-04 23:04 ` Lina Iyer 2016-08-04 23:04 ` [PATCH v3 11/15] drivers: firmware: psci: Allow OS Initiated suspend mode Lina Iyer 2016-08-04 23:04 ` Lina Iyer 2016-08-04 23:04 ` [PATCH v3 12/15] drivers: firmware: psci: Support cluster idle states for OS-Initiated Lina Iyer 2016-08-04 23:04 ` Lina Iyer 2016-08-04 23:05 ` [PATCH v3 13/15] dt/bindings: Add PSCI OS-Initiated PM Domains bindings Lina Iyer 2016-08-04 23:05 ` Lina Iyer 2016-08-05 14:44 ` Lina Iyer 2016-08-05 14:44 ` Lina Iyer 2016-08-04 23:05 ` [PATCH v3 14/15] ARM64: dts: Add PSCI cpuidle support for MSM8916 Lina Iyer 2016-08-04 23:05 ` Lina Iyer [not found] ` <1470351902-43103-1-git-send-email-lina.iyer-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org> 2016-08-04 23:05 ` [PATCH v3 15/15] ARM64: dts: Define CPU power domain " Lina Iyer 2016-08-04 23:05 ` Lina Iyer 2016-08-10 15:27 ` Sudeep Holla 2016-08-10 15:27 ` Sudeep Holla 2016-08-10 17:35 ` Lina Iyer 2016-08-10 17:35 ` Lina Iyer 2016-08-11 9:30 ` Sudeep Holla 2016-08-11 9:30 ` Sudeep Holla
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