From: Beata Michalska <beata.michalska@arm.com> To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-pm@vger.kernel.org, sumitg@nvidia.com Cc: sudeep.holla@arm.covm, will@kernel.org, catalin.marinas@arm.com, viresh.kumar@linaro.org, rafael@kernel.org, ionela.voinescu@arm.com, yang@os.amperecomputing.com, linux-tegra@vger.kernel.org, Sudeep Holla <sudeep.holla@arm.com> Subject: [PATCH v2 1/2] arm64: Provide an AMU-based version of arch_freq_get_on_cpu Date: Mon, 27 Nov 2023 16:08:37 +0000 [thread overview] Message-ID: <20231127160838.1403404-2-beata.michalska@arm.com> (raw) In-Reply-To: <20231127160838.1403404-1-beata.michalska@arm.com> With the Frequency Invariance Engine (FIE) being already wired up with sched tick and making use of relevant (core counter and constant counter) AMU counters, getting the current frequency for a given CPU on supported platforms, can be achieved by utilizing the frequency scale factor which reflects an average CPU frequency for the last tick period length. Suggested-by: Ionela Voinescu <ionela.voinescu@arm.com> Signed-off-by: Beata Michalska <beata.michalska@arm.com> Reviewed-by: Sudeep Holla <sudeep.holla@arm.com> --- Notes: Due to [1], if merged, there might be a need to modify the patch to accommodate changes [1] introduces: freq = cpufreq_get_hw_max_freq(cpu) >> SCHED_CAPACITY_SHIFT to freq = per_cpu(capacity_freq_ref, cpu); >> SCHED_CAPACITY_SHIFT [1] https://lore.kernel.org/linux-arm-kernel/20231121154349.GA1938@willie-the-truck/T/#mcb018d076dbce6f60ed2779634a9b6ffe622641e arch/arm64/kernel/topology.c | 39 ++++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c index 615c1a20129f..ae2445f6e7da 100644 --- a/arch/arm64/kernel/topology.c +++ b/arch/arm64/kernel/topology.c @@ -17,6 +17,7 @@ #include <linux/cpufreq.h> #include <linux/init.h> #include <linux/percpu.h> +#include <linux/sched/isolation.h> #include <asm/cpu.h> #include <asm/cputype.h> @@ -186,6 +187,44 @@ static void amu_scale_freq_tick(void) this_cpu_write(arch_freq_scale, (unsigned long)scale); } +unsigned int arch_freq_get_on_cpu(int cpu) +{ + unsigned int freq; + u64 scale; + + if (!cpumask_test_cpu(cpu, amu_fie_cpus)) + return 0; + + /* + * For those CPUs that are in full dynticks mode, try an alternative + * source for the counters (and thus freq scale), + * if available for given policy + */ + if (!housekeeping_cpu(cpu, HK_TYPE_TICK)) { + struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); + int ref_cpu = nr_cpu_ids; + + if (cpumask_intersects(housekeeping_cpumask(HK_TYPE_TICK), + policy->cpus)) + ref_cpu = cpumask_nth_and(cpu, policy->cpus, + housekeeping_cpumask(HK_TYPE_TICK)); + cpufreq_cpu_put(policy); + if (ref_cpu >= nr_cpu_ids) + return 0; + cpu = ref_cpu; + } + + /* + * Reversed computation to the one used to determine + * the arch_freq_scale value + * (see amu_scale_freq_tick for details) + */ + scale = per_cpu(arch_freq_scale, cpu); + freq = cpufreq_get_hw_max_freq(cpu) >> SCHED_CAPACITY_SHIFT; + freq *= scale; + return freq; +} + static struct scale_freq_data amu_sfd = { .source = SCALE_FREQ_SOURCE_ARCH, .set_freq_scale = amu_scale_freq_tick, -- 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, linux-pm@vger.kernel.org, sumitg@nvidia.com Cc: sudeep.holla@arm.covm, will@kernel.org, catalin.marinas@arm.com, viresh.kumar@linaro.org, rafael@kernel.org, ionela.voinescu@arm.com, yang@os.amperecomputing.com, linux-tegra@vger.kernel.org, Sudeep Holla <sudeep.holla@arm.com> Subject: [PATCH v2 1/2] arm64: Provide an AMU-based version of arch_freq_get_on_cpu Date: Mon, 27 Nov 2023 16:08:37 +0000 [thread overview] Message-ID: <20231127160838.1403404-2-beata.michalska@arm.com> (raw) In-Reply-To: <20231127160838.1403404-1-beata.michalska@arm.com> With the Frequency Invariance Engine (FIE) being already wired up with sched tick and making use of relevant (core counter and constant counter) AMU counters, getting the current frequency for a given CPU on supported platforms, can be achieved by utilizing the frequency scale factor which reflects an average CPU frequency for the last tick period length. Suggested-by: Ionela Voinescu <ionela.voinescu@arm.com> Signed-off-by: Beata Michalska <beata.michalska@arm.com> Reviewed-by: Sudeep Holla <sudeep.holla@arm.com> --- Notes: Due to [1], if merged, there might be a need to modify the patch to accommodate changes [1] introduces: freq = cpufreq_get_hw_max_freq(cpu) >> SCHED_CAPACITY_SHIFT to freq = per_cpu(capacity_freq_ref, cpu); >> SCHED_CAPACITY_SHIFT [1] https://lore.kernel.org/linux-arm-kernel/20231121154349.GA1938@willie-the-truck/T/#mcb018d076dbce6f60ed2779634a9b6ffe622641e arch/arm64/kernel/topology.c | 39 ++++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c index 615c1a20129f..ae2445f6e7da 100644 --- a/arch/arm64/kernel/topology.c +++ b/arch/arm64/kernel/topology.c @@ -17,6 +17,7 @@ #include <linux/cpufreq.h> #include <linux/init.h> #include <linux/percpu.h> +#include <linux/sched/isolation.h> #include <asm/cpu.h> #include <asm/cputype.h> @@ -186,6 +187,44 @@ static void amu_scale_freq_tick(void) this_cpu_write(arch_freq_scale, (unsigned long)scale); } +unsigned int arch_freq_get_on_cpu(int cpu) +{ + unsigned int freq; + u64 scale; + + if (!cpumask_test_cpu(cpu, amu_fie_cpus)) + return 0; + + /* + * For those CPUs that are in full dynticks mode, try an alternative + * source for the counters (and thus freq scale), + * if available for given policy + */ + if (!housekeeping_cpu(cpu, HK_TYPE_TICK)) { + struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); + int ref_cpu = nr_cpu_ids; + + if (cpumask_intersects(housekeeping_cpumask(HK_TYPE_TICK), + policy->cpus)) + ref_cpu = cpumask_nth_and(cpu, policy->cpus, + housekeeping_cpumask(HK_TYPE_TICK)); + cpufreq_cpu_put(policy); + if (ref_cpu >= nr_cpu_ids) + return 0; + cpu = ref_cpu; + } + + /* + * Reversed computation to the one used to determine + * the arch_freq_scale value + * (see amu_scale_freq_tick for details) + */ + scale = per_cpu(arch_freq_scale, cpu); + freq = cpufreq_get_hw_max_freq(cpu) >> SCHED_CAPACITY_SHIFT; + freq *= scale; + return freq; +} + static struct scale_freq_data amu_sfd = { .source = SCALE_FREQ_SOURCE_ARCH, .set_freq_scale = amu_scale_freq_tick, -- 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:[~2023-11-27 16:09 UTC|newest] Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-11-27 16:08 [PATCH v2 0/2] Add support for AArch64 AMUv1-based arch_freq_get_on_cpu Beata Michalska 2023-11-27 16:08 ` Beata Michalska 2023-11-27 16:08 ` Beata Michalska [this message] 2023-11-27 16:08 ` [PATCH v2 1/2] arm64: Provide an AMU-based version of arch_freq_get_on_cpu Beata Michalska 2023-11-28 15:13 ` Ionela Voinescu 2023-11-28 15:13 ` Ionela Voinescu 2024-02-02 9:20 ` Beata Michalska 2024-02-02 9:20 ` Beata Michalska 2024-02-22 19:55 ` Vanshidhar Konda 2024-02-22 19:55 ` Vanshidhar Konda 2023-11-27 16:08 ` [PATCH v2 2/2] cpufreq: Wire-up arch-flavored freq info into cpufreq_verify_current_freq Beata Michalska 2023-11-27 16:08 ` Beata Michalska 2023-11-28 14:01 ` Ionela Voinescu 2023-11-28 14:01 ` Ionela Voinescu 2023-12-01 13:02 ` Sumit Gupta 2023-12-01 13:02 ` Sumit Gupta 2023-12-05 11:05 ` Ionela Voinescu 2023-12-05 11:05 ` Ionela Voinescu 2023-12-06 13:28 ` Sumit Gupta 2023-12-06 13:28 ` Sumit Gupta 2023-12-07 9:22 ` Ionela Voinescu 2023-12-07 9:22 ` Ionela Voinescu 2023-12-08 15:34 ` Sumit Gupta 2023-12-08 15:34 ` Sumit Gupta 2024-02-02 9:14 ` Beata Michalska 2024-02-02 9:14 ` Beata Michalska 2023-12-06 20:41 ` Rafael J. Wysocki 2023-12-06 20:41 ` Rafael J. Wysocki 2024-02-02 9:05 ` Beata Michalska 2024-02-02 9:05 ` Beata Michalska
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