| Message ID | f72383d451710fc4bc36e7e3015deba40fbe28f3.1614580695.git.viresh.kumar@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | cpufreq: cppc: Add support for frequency invariance | expand |
Hey, On Monday 01 Mar 2021 at 12:21:18 (+0530), Viresh Kumar wrote: > The Frequency Invariance Engine (FIE) is providing a frequency scaling > correction factor that helps achieve more accurate load-tracking. > > Normally, this scaling factor can be obtained directly with the help of > the cpufreq drivers as they know the exact frequency the hardware is > running at. But that isn't the case for CPPC cpufreq driver. > > Another way of obtaining that is using the arch specific counter > support, which is already present in kernel, but that hardware is > optional for platforms. > > This patch updates the CPPC driver to register itself with the topology > core to provide its own implementation (cppc_scale_freq_tick()) of > topology_scale_freq_tick() which gets called by the scheduler on every > tick. Note that the arch specific counters have higher priority than > CPPC counters, if available, though the CPPC driver doesn't need to have > any special handling for that. > > On an invocation of cppc_scale_freq_tick(), we schedule an irq work > (since we reach here from hard-irq context), which then schedules a > normal work item and cppc_scale_freq_workfn() updates the per_cpu > freq_scale variable based on the counter updates since the last tick. > > To allow platforms to disable frequency invariance support if they want, ^ this CPPC counter-based frequency invariance support.. (disabling this config will not disable cpufreq or arch counter-based FIE) > this is all done under CONFIG_ACPI_CPPC_CPUFREQ_FIE, which is enabled by > default. > > This also exports sched_setattr_nocheck() as the CPPC driver can be > built as a module. > > Cc: Ionela Voinescu <ionela.voinescu@arm.com> > Cc: linux-acpi@vger.kernel.org > Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> > --- > drivers/cpufreq/Kconfig.arm | 9 ++ > drivers/cpufreq/cppc_cpufreq.c | 244 +++++++++++++++++++++++++++++++-- > include/linux/arch_topology.h | 1 + > kernel/sched/core.c | 1 + > 4 files changed, 243 insertions(+), 12 deletions(-) > > diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm > index e65e0a43be64..a3e2d6dfea70 100644 > --- a/drivers/cpufreq/Kconfig.arm > +++ b/drivers/cpufreq/Kconfig.arm > @@ -19,6 +19,15 @@ config ACPI_CPPC_CPUFREQ > > If in doubt, say N. > > +config ACPI_CPPC_CPUFREQ_FIE > + bool "Frequency Invariance support for CPPC cpufreq driver" > + depends on ACPI_CPPC_CPUFREQ It also depends on GENERIC_ARCH_TOPOLOGY. > + default y > + help > + This enables frequency invariance support for CPPC cpufreq driver. ^^^^^^^^^^^^^^^^^^^^^^^^ s//based on CPPC counters. .. or more detailed: This extends frequency invariance support in the CPPC cpufreq driver, by using CPPC delivered and reference performance counters. > + > + If in doubt, say N. > + > config ARM_ALLWINNER_SUN50I_CPUFREQ_NVMEM > tristate "Allwinner nvmem based SUN50I CPUFreq driver" > depends on ARCH_SUNXI > diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c > index 8a482c434ea6..c4580a37a1b1 100644 > --- a/drivers/cpufreq/cppc_cpufreq.c > +++ b/drivers/cpufreq/cppc_cpufreq.c [..] > +static void cppc_freq_invariance_policy_init(struct cpufreq_policy *policy, > + struct cppc_cpudata *cpu_data) > +{ > + struct cppc_freq_invariance *cppc_fi; > + int i; > + > + if (cppc_cpufreq_driver.get == hisi_cppc_cpufreq_get_rate) > + return; > + > + for_each_cpu(i, policy->cpus) { > + cppc_fi = &per_cpu(cppc_freq_inv, i); > + cppc_fi->cpu = i; > + cppc_fi->cpu_data = cpu_data; > + kthread_init_work(&cppc_fi->work, cppc_scale_freq_workfn); > + init_irq_work(&cppc_fi->irq_work, cppc_irq_work); > + } > +} > + > +static void cppc_freq_invariance_exit(void) > +{ > + struct cppc_freq_invariance *cppc_fi; > + int i; > + > + if (cppc_cpufreq_driver.get == hisi_cppc_cpufreq_get_rate) > + return; > + > + topology_clear_scale_freq_source(SCALE_FREQ_SOURCE_CPPC, cpu_present_mask); > + > + for_each_possible_cpu(i) { > + cppc_fi = &per_cpu(cppc_freq_inv, i); > + irq_work_sync(&cppc_fi->irq_work); > + } > + > + kthread_destroy_worker(kworker_fie); > + kworker_fie = NULL; > +} > + > +static void __init cppc_freq_invariance_init(void) > +{ > + struct cppc_perf_fb_ctrs fb_ctrs = {0}; > + struct cppc_freq_invariance *cppc_fi; > + struct sched_attr attr = { > + .size = sizeof(struct sched_attr), > + .sched_policy = SCHED_DEADLINE, > + .sched_nice = 0, > + .sched_priority = 0, > + /* > + * Fake (unused) bandwidth; workaround to "fix" > + * priority inheritance. > + */ > + .sched_runtime = 1000000, > + .sched_deadline = 10000000, > + .sched_period = 10000000, > + }; > + int i, ret; > + > + if (cppc_cpufreq_driver.get == hisi_cppc_cpufreq_get_rate) > + return; > + > + kworker_fie = kthread_create_worker(0, "cppc_fie"); > + if (IS_ERR(kworker_fie)) > + return; > + > + ret = sched_setattr_nocheck(kworker_fie->task, &attr); > + if (ret) { > + pr_warn("%s: failed to set SCHED_DEADLINE: %d\n", __func__, > + ret); > + kthread_destroy_worker(kworker_fie); > + return; > + } > + Nit: to me it makes more sense to move the code below to cppc_freq_invariance_policy_init(). It seems a bit strange to do part of the initialization of the per-cpu information there, and part here. But I do understand the reasons for it. Moving the code below would also save some cycles going through the CPUs again and will mimic the frequency invariance setup process in the arm64 topology, where we do amu_fie_setup() at policy creation time. It's not a big deal so I'll leave it up to you. > + for_each_possible_cpu(i) { > + cppc_fi = &per_cpu(cppc_freq_inv, i); > + > + /* A policy failed to initialize, abort */ > + if (unlikely(!cppc_fi->cpu_data)) > + return cppc_freq_invariance_exit(); > + > + ret = cppc_get_perf_ctrs(i, &fb_ctrs); > + if (ret) { > + pr_warn("%s: failed to read perf counters: %d\n", > + __func__, ret); > + return cppc_freq_invariance_exit(); > + } > + > + cppc_fi->prev_perf_fb_ctrs = fb_ctrs; > + } > + > + /* Register for freq-invariance */ > + topology_set_scale_freq_source(&cppc_sftd, cpu_present_mask); > +} After another very quick round of testing: Reviewed-by: Ionela Voinescu <ionela.voinescu@arm.com> Tested-by: Ionela Voinescu <ionela.voinescu@arm.com> I did not get the chance to test on ThunderX2 yet, but if you are happy with your testing on it, I won't delay this any further. Thanks, Ionela.
On Tue, 9 Mar 2021 at 16:10, Ionela Voinescu <ionela.voinescu@arm.com> wrote: > > Hey, > > On Monday 01 Mar 2021 at 12:21:18 (+0530), Viresh Kumar wrote: > > The Frequency Invariance Engine (FIE) is providing a frequency scaling > > correction factor that helps achieve more accurate load-tracking. > > > > Normally, this scaling factor can be obtained directly with the help of > > the cpufreq drivers as they know the exact frequency the hardware is > > running at. But that isn't the case for CPPC cpufreq driver. > > > > Another way of obtaining that is using the arch specific counter > > support, which is already present in kernel, but that hardware is > > optional for platforms. > > > > This patch updates the CPPC driver to register itself with the topology > > core to provide its own implementation (cppc_scale_freq_tick()) of > > topology_scale_freq_tick() which gets called by the scheduler on every > > tick. Note that the arch specific counters have higher priority than > > CPPC counters, if available, though the CPPC driver doesn't need to have > > any special handling for that. > > > > On an invocation of cppc_scale_freq_tick(), we schedule an irq work > > (since we reach here from hard-irq context), which then schedules a > > normal work item and cppc_scale_freq_workfn() updates the per_cpu > > freq_scale variable based on the counter updates since the last tick. > > > > To allow platforms to disable frequency invariance support if they want, > ^ > this CPPC counter-based frequency invariance > support.. > > (disabling this config will not disable cpufreq or arch counter-based FIE) > > > this is all done under CONFIG_ACPI_CPPC_CPUFREQ_FIE, which is enabled by > > default. > > > > This also exports sched_setattr_nocheck() as the CPPC driver can be > > built as a module. > > > > Cc: Ionela Voinescu <ionela.voinescu@arm.com> > > Cc: linux-acpi@vger.kernel.org > > Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> > > --- > > drivers/cpufreq/Kconfig.arm | 9 ++ > > drivers/cpufreq/cppc_cpufreq.c | 244 +++++++++++++++++++++++++++++++-- > > include/linux/arch_topology.h | 1 + > > kernel/sched/core.c | 1 + > > 4 files changed, 243 insertions(+), 12 deletions(-) > > > > diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm > > index e65e0a43be64..a3e2d6dfea70 100644 > > --- a/drivers/cpufreq/Kconfig.arm > > +++ b/drivers/cpufreq/Kconfig.arm > > @@ -19,6 +19,15 @@ config ACPI_CPPC_CPUFREQ > > > > If in doubt, say N. > > > > +config ACPI_CPPC_CPUFREQ_FIE > > + bool "Frequency Invariance support for CPPC cpufreq driver" > > + depends on ACPI_CPPC_CPUFREQ > > It also depends on GENERIC_ARCH_TOPOLOGY. > > > + default y > > + help > > + This enables frequency invariance support for CPPC cpufreq driver. > ^^^^^^^^^^^^^^^^^^^^^^^^ > s//based on CPPC counters. > > .. or more detailed: This extends frequency invariance support in the > CPPC cpufreq driver, by using CPPC delivered and reference performance > counters. > > > + > > + If in doubt, say N. > > + > > config ARM_ALLWINNER_SUN50I_CPUFREQ_NVMEM > > tristate "Allwinner nvmem based SUN50I CPUFreq driver" > > depends on ARCH_SUNXI > > diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c > > index 8a482c434ea6..c4580a37a1b1 100644 > > --- a/drivers/cpufreq/cppc_cpufreq.c > > +++ b/drivers/cpufreq/cppc_cpufreq.c > [..] > > +static void cppc_freq_invariance_policy_init(struct cpufreq_policy *policy, > > + struct cppc_cpudata *cpu_data) > > +{ > > + struct cppc_freq_invariance *cppc_fi; > > + int i; > > + > > + if (cppc_cpufreq_driver.get == hisi_cppc_cpufreq_get_rate) > > + return; > > + > > + for_each_cpu(i, policy->cpus) { > > + cppc_fi = &per_cpu(cppc_freq_inv, i); > > + cppc_fi->cpu = i; > > + cppc_fi->cpu_data = cpu_data; > > + kthread_init_work(&cppc_fi->work, cppc_scale_freq_workfn); > > + init_irq_work(&cppc_fi->irq_work, cppc_irq_work); > > + } > > +} > > + > > +static void cppc_freq_invariance_exit(void) > > +{ > > + struct cppc_freq_invariance *cppc_fi; > > + int i; > > + > > + if (cppc_cpufreq_driver.get == hisi_cppc_cpufreq_get_rate) > > + return; > > + > > + topology_clear_scale_freq_source(SCALE_FREQ_SOURCE_CPPC, cpu_present_mask); > > + > > + for_each_possible_cpu(i) { > > + cppc_fi = &per_cpu(cppc_freq_inv, i); > > + irq_work_sync(&cppc_fi->irq_work); > > + } > > + > > + kthread_destroy_worker(kworker_fie); > > + kworker_fie = NULL; > > +} > > + > > +static void __init cppc_freq_invariance_init(void) > > +{ > > + struct cppc_perf_fb_ctrs fb_ctrs = {0}; > > + struct cppc_freq_invariance *cppc_fi; > > + struct sched_attr attr = { > > + .size = sizeof(struct sched_attr), > > + .sched_policy = SCHED_DEADLINE, > > + .sched_nice = 0, > > + .sched_priority = 0, > > + /* > > + * Fake (unused) bandwidth; workaround to "fix" > > + * priority inheritance. > > + */ > > + .sched_runtime = 1000000, > > + .sched_deadline = 10000000, > > + .sched_period = 10000000, > > + }; > > + int i, ret; > > + > > + if (cppc_cpufreq_driver.get == hisi_cppc_cpufreq_get_rate) > > + return; > > + > > + kworker_fie = kthread_create_worker(0, "cppc_fie"); > > + if (IS_ERR(kworker_fie)) > > + return; > > + > > + ret = sched_setattr_nocheck(kworker_fie->task, &attr); > > + if (ret) { > > + pr_warn("%s: failed to set SCHED_DEADLINE: %d\n", __func__, > > + ret); > > + kthread_destroy_worker(kworker_fie); > > + return; > > + } > > + > > Nit: to me it makes more sense to move the code below to > cppc_freq_invariance_policy_init(). It seems a bit strange to do part of > the initialization of the per-cpu information there, and part here. But > I do understand the reasons for it. Moving the code below would also > save some cycles going through the CPUs again and will mimic the > frequency invariance setup process in the arm64 topology, where we do > amu_fie_setup() at policy creation time. > > It's not a big deal so I'll leave it up to you. > > > + for_each_possible_cpu(i) { > > + cppc_fi = &per_cpu(cppc_freq_inv, i); > > + > > + /* A policy failed to initialize, abort */ > > + if (unlikely(!cppc_fi->cpu_data)) > > + return cppc_freq_invariance_exit(); > > + > > + ret = cppc_get_perf_ctrs(i, &fb_ctrs); > > + if (ret) { > > + pr_warn("%s: failed to read perf counters: %d\n", > > + __func__, ret); > > + return cppc_freq_invariance_exit(); > > + } > > + > > + cppc_fi->prev_perf_fb_ctrs = fb_ctrs; > > + } > > + > > + /* Register for freq-invariance */ > > + topology_set_scale_freq_source(&cppc_sftd, cpu_present_mask); > > +} > > After another very quick round of testing: > > Reviewed-by: Ionela Voinescu <ionela.voinescu@arm.com> > Tested-by: Ionela Voinescu <ionela.voinescu@arm.com> > > I did not get the chance to test on ThunderX2 yet, but if you are happy > with your testing on it, I won't delay this any further. I have just run some functional tests on thx2 with rt-app: I have run a periodic task (6ms running / 30ms periods) at different frequencies (2.5Ghz, 2Ghz, 1.5Ghz, 1.333Ghz, 1Ghz) and the PELT signals stays the same for all frequencies. Tested-by: Vincent Guittot <vincent.guittot@linaro.org> > > Thanks, > Ionela.
diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm index e65e0a43be64..a3e2d6dfea70 100644 --- a/drivers/cpufreq/Kconfig.arm +++ b/drivers/cpufreq/Kconfig.arm @@ -19,6 +19,15 @@ config ACPI_CPPC_CPUFREQ If in doubt, say N. +config ACPI_CPPC_CPUFREQ_FIE + bool "Frequency Invariance support for CPPC cpufreq driver" + depends on ACPI_CPPC_CPUFREQ + default y + help + This enables frequency invariance support for CPPC cpufreq driver. + + If in doubt, say N. + config ARM_ALLWINNER_SUN50I_CPUFREQ_NVMEM tristate "Allwinner nvmem based SUN50I CPUFreq driver" depends on ARCH_SUNXI diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c index 8a482c434ea6..c4580a37a1b1 100644 --- a/drivers/cpufreq/cppc_cpufreq.c +++ b/drivers/cpufreq/cppc_cpufreq.c @@ -10,14 +10,18 @@ #define pr_fmt(fmt) "CPPC Cpufreq:" fmt +#include <linux/arch_topology.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/delay.h> #include <linux/cpu.h> #include <linux/cpufreq.h> #include <linux/dmi.h> +#include <linux/irq_work.h> +#include <linux/kthread.h> #include <linux/time.h> #include <linux/vmalloc.h> +#include <uapi/linux/sched/types.h> #include <asm/unaligned.h> @@ -57,6 +61,203 @@ static struct cppc_workaround_oem_info wa_info[] = { } }; +#ifdef CONFIG_ACPI_CPPC_CPUFREQ_FIE + +/* Frequency invariance support */ +struct cppc_freq_invariance { + int cpu; + struct irq_work irq_work; + struct kthread_work work; + struct cppc_perf_fb_ctrs prev_perf_fb_ctrs; + struct cppc_cpudata *cpu_data; +}; + +static DEFINE_PER_CPU(struct cppc_freq_invariance, cppc_freq_inv); +static struct kthread_worker *kworker_fie; + +static struct cpufreq_driver cppc_cpufreq_driver; +static unsigned int hisi_cppc_cpufreq_get_rate(unsigned int cpu); +static int cppc_perf_from_fbctrs(struct cppc_cpudata *cpu_data, + struct cppc_perf_fb_ctrs fb_ctrs_t0, + struct cppc_perf_fb_ctrs fb_ctrs_t1); + +/** + * cppc_scale_freq_workfn - CPPC freq_scale updater for frequency invariance + * @work: The work item. + * + * The CPPC driver register itself with the topology core to provide its own + * implementation (cppc_scale_freq_tick()) of topology_scale_freq_tick() which + * gets called by the scheduler on every tick. + * + * Note that the arch specific counters have higher priority than CPPC counters, + * if available, though the CPPC driver doesn't need to have any special + * handling for that. + * + * On an invocation of cppc_scale_freq_tick(), we schedule an irq work (since we + * reach here from hard-irq context), which then schedules a normal work item + * and cppc_scale_freq_workfn() updates the per_cpu freq_scale variable based on + * the counter updates since the last tick. + */ +static void cppc_scale_freq_workfn(struct kthread_work *work) +{ + struct cppc_freq_invariance *cppc_fi; + struct cppc_perf_fb_ctrs fb_ctrs = {0}; + struct cppc_cpudata *cpu_data; + unsigned long local_freq_scale; + u64 perf; + + cppc_fi = container_of(work, struct cppc_freq_invariance, work); + cpu_data = cppc_fi->cpu_data; + + if (cppc_get_perf_ctrs(cppc_fi->cpu, &fb_ctrs)) { + pr_warn("%s: failed to read perf counters\n", __func__); + return; + } + + cppc_fi->prev_perf_fb_ctrs = fb_ctrs; + perf = cppc_perf_from_fbctrs(cpu_data, cppc_fi->prev_perf_fb_ctrs, + fb_ctrs); + + perf <<= SCHED_CAPACITY_SHIFT; + local_freq_scale = div64_u64(perf, cpu_data->perf_caps.highest_perf); + if (WARN_ON(local_freq_scale > 1024)) + local_freq_scale = 1024; + + per_cpu(freq_scale, cppc_fi->cpu) = local_freq_scale; +} + +static void cppc_irq_work(struct irq_work *irq_work) +{ + struct cppc_freq_invariance *cppc_fi; + + cppc_fi = container_of(irq_work, struct cppc_freq_invariance, irq_work); + kthread_queue_work(kworker_fie, &cppc_fi->work); +} + +static void cppc_scale_freq_tick(void) +{ + struct cppc_freq_invariance *cppc_fi = &per_cpu(cppc_freq_inv, smp_processor_id()); + + /* + * cppc_get_perf_ctrs() can potentially sleep, call that from the right + * context. + */ + irq_work_queue(&cppc_fi->irq_work); +} + +static struct scale_freq_data cppc_sftd = { + .source = SCALE_FREQ_SOURCE_CPPC, + .set_freq_scale = cppc_scale_freq_tick, +}; + +static void cppc_freq_invariance_policy_init(struct cpufreq_policy *policy, + struct cppc_cpudata *cpu_data) +{ + struct cppc_freq_invariance *cppc_fi; + int i; + + if (cppc_cpufreq_driver.get == hisi_cppc_cpufreq_get_rate) + return; + + for_each_cpu(i, policy->cpus) { + cppc_fi = &per_cpu(cppc_freq_inv, i); + cppc_fi->cpu = i; + cppc_fi->cpu_data = cpu_data; + kthread_init_work(&cppc_fi->work, cppc_scale_freq_workfn); + init_irq_work(&cppc_fi->irq_work, cppc_irq_work); + } +} + +static void cppc_freq_invariance_exit(void) +{ + struct cppc_freq_invariance *cppc_fi; + int i; + + if (cppc_cpufreq_driver.get == hisi_cppc_cpufreq_get_rate) + return; + + topology_clear_scale_freq_source(SCALE_FREQ_SOURCE_CPPC, cpu_present_mask); + + for_each_possible_cpu(i) { + cppc_fi = &per_cpu(cppc_freq_inv, i); + irq_work_sync(&cppc_fi->irq_work); + } + + kthread_destroy_worker(kworker_fie); + kworker_fie = NULL; +} + +static void __init cppc_freq_invariance_init(void) +{ + struct cppc_perf_fb_ctrs fb_ctrs = {0}; + struct cppc_freq_invariance *cppc_fi; + struct sched_attr attr = { + .size = sizeof(struct sched_attr), + .sched_policy = SCHED_DEADLINE, + .sched_nice = 0, + .sched_priority = 0, + /* + * Fake (unused) bandwidth; workaround to "fix" + * priority inheritance. + */ + .sched_runtime = 1000000, + .sched_deadline = 10000000, + .sched_period = 10000000, + }; + int i, ret; + + if (cppc_cpufreq_driver.get == hisi_cppc_cpufreq_get_rate) + return; + + kworker_fie = kthread_create_worker(0, "cppc_fie"); + if (IS_ERR(kworker_fie)) + return; + + ret = sched_setattr_nocheck(kworker_fie->task, &attr); + if (ret) { + pr_warn("%s: failed to set SCHED_DEADLINE: %d\n", __func__, + ret); + kthread_destroy_worker(kworker_fie); + return; + } + + for_each_possible_cpu(i) { + cppc_fi = &per_cpu(cppc_freq_inv, i); + + /* A policy failed to initialize, abort */ + if (unlikely(!cppc_fi->cpu_data)) + return cppc_freq_invariance_exit(); + + ret = cppc_get_perf_ctrs(i, &fb_ctrs); + if (ret) { + pr_warn("%s: failed to read perf counters: %d\n", + __func__, ret); + return cppc_freq_invariance_exit(); + } + + cppc_fi->prev_perf_fb_ctrs = fb_ctrs; + } + + /* Register for freq-invariance */ + topology_set_scale_freq_source(&cppc_sftd, cpu_present_mask); +} + +#else +static inline void +cppc_freq_invariance_policy_init(struct cpufreq_policy *policy, + struct cppc_cpudata *cpu_data) +{ +} + +static inline void cppc_freq_invariance_exit(void) +{ +} + +static inline void cppc_freq_invariance_init(void) +{ +} +#endif /* CONFIG_ACPI_CPPC_CPUFREQ_FIE */ + /* Callback function used to retrieve the max frequency from DMI */ static void cppc_find_dmi_mhz(const struct dmi_header *dm, void *private) { @@ -355,9 +556,12 @@ static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy) cpu_data->perf_ctrls.desired_perf = caps->highest_perf; ret = cppc_set_perf(cpu, &cpu_data->perf_ctrls); - if (ret) + if (ret) { pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n", caps->highest_perf, cpu, ret); + } else { + cppc_freq_invariance_policy_init(policy, cpu_data); + } return ret; } @@ -370,12 +574,12 @@ static inline u64 get_delta(u64 t1, u64 t0) return (u32)t1 - (u32)t0; } -static int cppc_get_rate_from_fbctrs(struct cppc_cpudata *cpu_data, - struct cppc_perf_fb_ctrs fb_ctrs_t0, - struct cppc_perf_fb_ctrs fb_ctrs_t1) +static int cppc_perf_from_fbctrs(struct cppc_cpudata *cpu_data, + struct cppc_perf_fb_ctrs fb_ctrs_t0, + struct cppc_perf_fb_ctrs fb_ctrs_t1) { u64 delta_reference, delta_delivered; - u64 reference_perf, delivered_perf; + u64 reference_perf; reference_perf = fb_ctrs_t0.reference_perf; @@ -384,12 +588,21 @@ static int cppc_get_rate_from_fbctrs(struct cppc_cpudata *cpu_data, delta_delivered = get_delta(fb_ctrs_t1.delivered, fb_ctrs_t0.delivered); - /* Check to avoid divide-by zero */ - if (delta_reference || delta_delivered) - delivered_perf = (reference_perf * delta_delivered) / - delta_reference; - else - delivered_perf = cpu_data->perf_ctrls.desired_perf; + /* Check to avoid divide-by zero and invalid delivered_perf */ + if (!delta_reference || !delta_delivered) + return cpu_data->perf_ctrls.desired_perf; + + return (reference_perf * delta_delivered) / delta_reference; +} + +static int cppc_get_rate_from_fbctrs(struct cppc_cpudata *cpu_data, + struct cppc_perf_fb_ctrs fb_ctrs_t0, + struct cppc_perf_fb_ctrs fb_ctrs_t1) +{ + u64 delivered_perf; + + delivered_perf = cppc_perf_from_fbctrs(cpu_data, fb_ctrs_t0, + fb_ctrs_t1); return cppc_cpufreq_perf_to_khz(cpu_data, delivered_perf); } @@ -514,6 +727,8 @@ static void cppc_check_hisi_workaround(void) static int __init cppc_cpufreq_init(void) { + int ret; + if ((acpi_disabled) || !acpi_cpc_valid()) return -ENODEV; @@ -521,7 +736,11 @@ static int __init cppc_cpufreq_init(void) cppc_check_hisi_workaround(); - return cpufreq_register_driver(&cppc_cpufreq_driver); + ret = cpufreq_register_driver(&cppc_cpufreq_driver); + if (!ret) + cppc_freq_invariance_init(); + + return ret; } static inline void free_cpu_data(void) @@ -538,6 +757,7 @@ static inline void free_cpu_data(void) static void __exit cppc_cpufreq_exit(void) { + cppc_freq_invariance_exit(); cpufreq_unregister_driver(&cppc_cpufreq_driver); free_cpu_data(); diff --git a/include/linux/arch_topology.h b/include/linux/arch_topology.h index 3bcfba5c21a7..47ac4b41c28d 100644 --- a/include/linux/arch_topology.h +++ b/include/linux/arch_topology.h @@ -37,6 +37,7 @@ bool topology_scale_freq_invariant(void); enum scale_freq_source { SCALE_FREQ_SOURCE_CPUFREQ = 0, SCALE_FREQ_SOURCE_ARCH, + SCALE_FREQ_SOURCE_CPPC, }; struct scale_freq_data { diff --git a/kernel/sched/core.c b/kernel/sched/core.c index ca2bb629595f..3adedc7b1725 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -6386,6 +6386,7 @@ int sched_setattr_nocheck(struct task_struct *p, const struct sched_attr *attr) { return __sched_setscheduler(p, attr, false, true); } +EXPORT_SYMBOL_GPL(sched_setattr_nocheck); /** * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
The Frequency Invariance Engine (FIE) is providing a frequency scaling correction factor that helps achieve more accurate load-tracking. Normally, this scaling factor can be obtained directly with the help of the cpufreq drivers as they know the exact frequency the hardware is running at. But that isn't the case for CPPC cpufreq driver. Another way of obtaining that is using the arch specific counter support, which is already present in kernel, but that hardware is optional for platforms. This patch updates the CPPC driver to register itself with the topology core to provide its own implementation (cppc_scale_freq_tick()) of topology_scale_freq_tick() which gets called by the scheduler on every tick. Note that the arch specific counters have higher priority than CPPC counters, if available, though the CPPC driver doesn't need to have any special handling for that. On an invocation of cppc_scale_freq_tick(), we schedule an irq work (since we reach here from hard-irq context), which then schedules a normal work item and cppc_scale_freq_workfn() updates the per_cpu freq_scale variable based on the counter updates since the last tick. To allow platforms to disable frequency invariance support if they want, this is all done under CONFIG_ACPI_CPPC_CPUFREQ_FIE, which is enabled by default. This also exports sched_setattr_nocheck() as the CPPC driver can be built as a module. Cc: Ionela Voinescu <ionela.voinescu@arm.com> Cc: linux-acpi@vger.kernel.org Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> --- drivers/cpufreq/Kconfig.arm | 9 ++ drivers/cpufreq/cppc_cpufreq.c | 244 +++++++++++++++++++++++++++++++-- include/linux/arch_topology.h | 1 + kernel/sched/core.c | 1 + 4 files changed, 243 insertions(+), 12 deletions(-) -- 2.25.0.rc1.19.g042ed3e048af