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author | Ionela Voinescu <ionela.voinescu@arm.com> | 2022-03-10 14:54:50 +0000 |
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committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2022-03-10 20:21:58 +0100 |
commit | 9924fbb51e0ae30b8d7eec7c1c839d74da9678b3 (patch) | |
tree | b9eba95a9ca8cc9f5b3735c479b217db0aa9c6bd /drivers | |
parent | 1132e6de11cfc334b44f609792664f1bc3055c52 (diff) | |
download | linux-9924fbb51e0ae30b8d7eec7c1c839d74da9678b3.tar.bz2 |
arch_topology: obtain cpu capacity using information from CPPC
Define topology_init_cpu_capacity_cppc() to use highest performance
values from _CPC objects to obtain and set maximum capacity information
for each CPU. acpi_cppc_processor_probe() is a good point at which to
trigger the initialization of CPU (u-arch) capacity values, as at this
point the highest performance values can be obtained from each CPU's
_CPC objects. Architectures can therefore use this functionality
through arch_init_invariance_cppc().
The performance scale used by CPPC is a unified scale for all CPUs in
the system. Therefore, by obtaining the raw highest performance values
from the _CPC objects, and normalizing them on the [0, 1024] capacity
scale, used by the task scheduler, we obtain the CPU capacity of each
CPU.
While an ACPI Notify(0x85) could alert about a change in the highest
performance value, which should in turn retrigger the CPU capacity
computations, this notification is not currently handled by the ACPI
processor driver. When supported, a call to arch_init_invariance_cppc()
would perform the update.
Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com>
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Tested-by: Valentin Schneider <valentin.schneider@arm.com>
Tested-by: Yicong Yang <yangyicong@hisilicon.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/base/arch_topology.c | 45 |
1 files changed, 42 insertions, 3 deletions
diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c index 976154140f0b..1d6636ebaac5 100644 --- a/drivers/base/arch_topology.c +++ b/drivers/base/arch_topology.c @@ -339,6 +339,46 @@ bool __init topology_parse_cpu_capacity(struct device_node *cpu_node, int cpu) return !ret; } +#ifdef CONFIG_ACPI_CPPC_LIB +#include <acpi/cppc_acpi.h> + +void topology_init_cpu_capacity_cppc(void) +{ + struct cppc_perf_caps perf_caps; + int cpu; + + if (likely(acpi_disabled || !acpi_cpc_valid())) + return; + + raw_capacity = kcalloc(num_possible_cpus(), sizeof(*raw_capacity), + GFP_KERNEL); + if (!raw_capacity) + return; + + for_each_possible_cpu(cpu) { + if (!cppc_get_perf_caps(cpu, &perf_caps) && + (perf_caps.highest_perf >= perf_caps.nominal_perf) && + (perf_caps.highest_perf >= perf_caps.lowest_perf)) { + raw_capacity[cpu] = perf_caps.highest_perf; + pr_debug("cpu_capacity: CPU%d cpu_capacity=%u (raw).\n", + cpu, raw_capacity[cpu]); + continue; + } + + pr_err("cpu_capacity: CPU%d missing/invalid highest performance.\n", cpu); + pr_err("cpu_capacity: partial information: fallback to 1024 for all CPUs\n"); + goto exit; + } + + topology_normalize_cpu_scale(); + schedule_work(&update_topology_flags_work); + pr_debug("cpu_capacity: cpu_capacity initialization done\n"); + +exit: + free_raw_capacity(); +} +#endif + #ifdef CONFIG_CPU_FREQ static cpumask_var_t cpus_to_visit; static void parsing_done_workfn(struct work_struct *work); @@ -387,9 +427,8 @@ static int __init register_cpufreq_notifier(void) int ret; /* - * on ACPI-based systems we need to use the default cpu capacity - * until we have the necessary code to parse the cpu capacity, so - * skip registering cpufreq notifier. + * On ACPI-based systems skip registering cpufreq notifier as cpufreq + * information is not needed for cpu capacity initialization. */ if (!acpi_disabled || !raw_capacity) return -EINVAL; |