From: Beata Michalska <beata.michalska@arm.com> To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, ionela.voinescu@arm.com, vanshikonda@os.amperecomputing.com Cc: sudeep.holla@arm.com, will@kernel.org, catalin.marinas@arm.com, vincent.guittot@linaro.org, sumitg@nvidia.com, yang@os.amperecomputing.com, lihuisong@huawei.com, viresh.kumar@linaro.org Subject: [PATCH v5 4/5] arm64: Update AMU-based frequency scale factor on entering idle Date: Wed, 17 Apr 2024 10:38:47 +0100 [thread overview] Message-ID: <20240417093848.1555462-5-beata.michalska@arm.com> (raw) In-Reply-To: <20240417093848.1555462-1-beata.michalska@arm.com> Now that the frequency scale factor has been activated for retrieving current frequency on a given CPU, trigger its update upon entering idle. This will, to an extent, allow querying last known frequency in a non-invasive way. It will also improve the frequency scale factor accuracy when a CPU entering idle did not receive a tick for a while. As a consequence, for idle cores, the reported frequency will be the last one observed before entering the idle state. Suggested-by: Vanshidhar Konda <vanshikonda@os.amperecomputing.com> Signed-off-by: Beata Michalska <beata.michalska@arm.com> --- arch/arm64/kernel/topology.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c index 475fdbf3032a..3110863ee18c 100644 --- a/arch/arm64/kernel/topology.c +++ b/arch/arm64/kernel/topology.c @@ -213,6 +213,19 @@ static __always_inline bool amu_fie_cpu_supported(unsigned int cpu) cpumask_test_cpu(cpu, amu_fie_cpus); } +void arch_cpu_idle_enter(void) +{ + unsigned int cpu = smp_processor_id(); + + if (!amu_fie_cpu_supported(cpu)) + return; + + /* Kick in AMU update but only if one has not happened already */ + if (housekeeping_cpu(cpu, HK_TYPE_TICK) && + time_is_before_jiffies(per_cpu(cpu_amu_samples.last_update, cpu))) + amu_scale_freq_tick(); +} + #define AMU_SAMPLE_EXP_MS 20 unsigned int arch_freq_get_on_cpu(int cpu) @@ -239,8 +252,8 @@ unsigned int arch_freq_get_on_cpu(int cpu) * this boils down to identifying an active cpu within the same freq * domain, if any. */ - if (!housekeeping_cpu(cpu, HK_TYPE_TICK) || - time_is_before_jiffies(last_update + msecs_to_jiffies(AMU_SAMPLE_EXP_MS))) { + if (!housekeeping_cpu(cpu, HK_TYPE_TICK) || (!idle_cpu(cpu) && + time_is_before_jiffies(last_update + msecs_to_jiffies(AMU_SAMPLE_EXP_MS)))) { struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); int ref_cpu = cpu; -- 2.25.1
WARNING: multiple messages have this Message-ID (diff)
From: Beata Michalska <beata.michalska@arm.com> To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, ionela.voinescu@arm.com, vanshikonda@os.amperecomputing.com Cc: sudeep.holla@arm.com, will@kernel.org, catalin.marinas@arm.com, vincent.guittot@linaro.org, sumitg@nvidia.com, yang@os.amperecomputing.com, lihuisong@huawei.com, viresh.kumar@linaro.org Subject: [PATCH v5 4/5] arm64: Update AMU-based frequency scale factor on entering idle Date: Wed, 17 Apr 2024 10:38:47 +0100 [thread overview] Message-ID: <20240417093848.1555462-5-beata.michalska@arm.com> (raw) In-Reply-To: <20240417093848.1555462-1-beata.michalska@arm.com> Now that the frequency scale factor has been activated for retrieving current frequency on a given CPU, trigger its update upon entering idle. This will, to an extent, allow querying last known frequency in a non-invasive way. It will also improve the frequency scale factor accuracy when a CPU entering idle did not receive a tick for a while. As a consequence, for idle cores, the reported frequency will be the last one observed before entering the idle state. Suggested-by: Vanshidhar Konda <vanshikonda@os.amperecomputing.com> Signed-off-by: Beata Michalska <beata.michalska@arm.com> --- arch/arm64/kernel/topology.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c index 475fdbf3032a..3110863ee18c 100644 --- a/arch/arm64/kernel/topology.c +++ b/arch/arm64/kernel/topology.c @@ -213,6 +213,19 @@ static __always_inline bool amu_fie_cpu_supported(unsigned int cpu) cpumask_test_cpu(cpu, amu_fie_cpus); } +void arch_cpu_idle_enter(void) +{ + unsigned int cpu = smp_processor_id(); + + if (!amu_fie_cpu_supported(cpu)) + return; + + /* Kick in AMU update but only if one has not happened already */ + if (housekeeping_cpu(cpu, HK_TYPE_TICK) && + time_is_before_jiffies(per_cpu(cpu_amu_samples.last_update, cpu))) + amu_scale_freq_tick(); +} + #define AMU_SAMPLE_EXP_MS 20 unsigned int arch_freq_get_on_cpu(int cpu) @@ -239,8 +252,8 @@ unsigned int arch_freq_get_on_cpu(int cpu) * this boils down to identifying an active cpu within the same freq * domain, if any. */ - if (!housekeeping_cpu(cpu, HK_TYPE_TICK) || - time_is_before_jiffies(last_update + msecs_to_jiffies(AMU_SAMPLE_EXP_MS))) { + if (!housekeeping_cpu(cpu, HK_TYPE_TICK) || (!idle_cpu(cpu) && + time_is_before_jiffies(last_update + msecs_to_jiffies(AMU_SAMPLE_EXP_MS)))) { struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); int ref_cpu = cpu; -- 2.25.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2024-04-17 9:39 UTC|newest] Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top 2024-04-17 9:38 [PATCH v5 0/5] Add support for AArch64 AMUv1-based arch_freq_get_on_cpu Beata Michalska 2024-04-17 9:38 ` Beata Michalska 2024-04-17 9:38 ` [PATCH v5 1/5] arch_topology: init capacity_freq_ref to 0 Beata Michalska 2024-04-17 9:38 ` Beata Michalska 2024-04-18 10:50 ` Sudeep Holla 2024-04-18 10:50 ` Sudeep Holla 2024-04-17 9:38 ` [PATCH v5 2/5] arm64: amu: Rule out potential use after free Beata Michalska 2024-04-17 9:38 ` Beata Michalska 2024-04-18 10:50 ` Sudeep Holla 2024-04-18 10:50 ` Sudeep Holla 2024-04-18 15:55 ` Beata Michalska 2024-04-18 15:55 ` Beata Michalska 2024-04-24 10:25 ` Sudeep Holla 2024-04-24 10:25 ` Sudeep Holla 2024-04-25 14:27 ` Beata Michalska 2024-04-25 14:27 ` Beata Michalska 2024-05-07 7:24 ` Ionela Voinescu 2024-05-07 7:24 ` Ionela Voinescu 2024-04-17 9:38 ` [PATCH v5 3/5] arm64: Provide an AMU-based version of arch_freq_get_on_cpu Beata Michalska 2024-04-17 9:38 ` Beata Michalska 2024-04-18 1:39 ` Vanshidhar Konda 2024-04-18 1:39 ` Vanshidhar Konda 2024-04-26 10:50 ` Beata Michalska 2024-04-26 10:50 ` Beata Michalska 2024-04-17 9:38 ` Beata Michalska [this message] 2024-04-17 9:38 ` [PATCH v5 4/5] arm64: Update AMU-based frequency scale factor on entering idle Beata Michalska 2024-04-17 9:38 ` [PATCH v5 5/5] cpufreq: Use arch specific feedback for cpuinfo_cur_freq Beata Michalska 2024-04-17 9:38 ` Beata Michalska
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