On Wed, Jan 06, 2021 at 09:30:25PM +1300, Barry Song wrote: > From: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx> > > Both ACPI and DT provide the ability to describe additional layers of > topology between that of individual cores and higher level constructs > such as the level at which the last level cache is shared. > In ACPI this can be represented in PPTT as a Processor Hierarchy > Node Structure [1] that is the parent of the CPU cores and in turn > has a parent Processor Hierarchy Nodes Structure representing > a higher level of topology. > > For example Kunpeng 920 has 6 clusters in each NUMA node, and each > cluster has 4 cpus. All clusters share L3 cache data, but each cluster > has local L3 tag. On the other hand, each clusters will share some > internal system bus. > > +-----------------------------------+ +---------+ > | +------+ +------+ +---------------------------+ | > | | CPU0 | | cpu1 | | +-----------+ | | > | +------+ +------+ | | | | | > | +----+ L3 | | | > | +------+ +------+ cluster | | tag | | | > | | CPU2 | | CPU3 | | | | | | > | +------+ +------+ | +-----------+ | | > | | | | > +-----------------------------------+ | | > +-----------------------------------+ | | > | +------+ +------+ +--------------------------+ | > | | | | | | +-----------+ | | > | +------+ +------+ | | | | | > | | | L3 | | | > | +------+ +------+ +----+ tag | | | > | | | | | | | | | | > | +------+ +------+ | +-----------+ | | > | | | | > +-----------------------------------+ | L3 | > | data | > +-----------------------------------+ | | > | +------+ +------+ | +-----------+ | | > | | | | | | | | | | > | +------+ +------+ +----+ L3 | | | > | | | tag | | | > | +------+ +------+ | | | | | > | | | | | ++ +-----------+ | | > | +------+ +------+ |---------------------------+ | > +-----------------------------------| | | > +-----------------------------------| | | > | +------+ +------+ +---------------------------+ | > | | | | | | +-----------+ | | > | +------+ +------+ | | | | | > | +----+ L3 | | | > | +------+ +------+ | | tag | | | > | | | | | | | | | | > | +------+ +------+ | +-----------+ | | > | | | | > +-----------------------------------+ | | > +-----------------------------------+ | | > | +------+ +------+ +--------------------------+ | > | | | | | | +-----------+ | | > | +------+ +------+ | | | | | > | | | L3 | | | > | +------+ +------+ +---+ tag | | | > | | | | | | | | | | > | +------+ +------+ | +-----------+ | | > | | | | > +-----------------------------------+ | | > +-----------------------------------+ ++ | > | +------+ +------+ +--------------------------+ | > | | | | | | +-----------+ | | > | +------+ +------+ | | | | | > | | | L3 | | | > | +------+ +------+ +--+ tag | | | > | | | | | | | | | | > | +------+ +------+ | +-----------+ | | > | | +---------+ > +-----------------------------------+ > > That means the cost to transfer ownership of a cacheline between CPUs > within a cluster is lower than between CPUs in different clusters on > the same die. Hence, it can make sense to tell the scheduler to use > the cache affinity of the cluster to make better decision on thread > migration. > > This patch simply exposes this information to userspace libraries > like hwloc by providing cluster_cpus and related sysfs attributes. > PoC of HWLOC support at [2]. > > Note this patch only handle the ACPI case. > > Special consideration is needed for SMT processors, where it is > necessary to move 2 levels up the hierarchy from the leaf nodes > (thus skipping the processor core level). > > Currently the ID provided is the offset of the Processor > Hierarchy Nodes Structure within PPTT. Whilst this is unique > it is not terribly elegant so alternative suggestions welcome. > > Note that arm64 / ACPI does not provide any means of identifying > a die level in the topology but that may be unrelate to the cluster > level. > > [1] ACPI Specification 6.3 - section 5.2.29.1 processor hierarchy node > structure (Type 0) > [2] https://github.com/hisilicon/hwloc/tree/linux-cluster > > Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx> > Signed-off-by: Barry Song <song.bao.hua@xxxxxxxxxxxxx> > --- > -v3: > * no real change(v2 comments not addressed); > * rebased againest 5.11-rc2; > > Documentation/admin-guide/cputopology.rst | 26 +++++++++++--- > arch/arm64/kernel/topology.c | 2 ++ > drivers/acpi/pptt.c | 60 +++++++++++++++++++++++++++++++ > drivers/base/arch_topology.c | 14 ++++++++ > drivers/base/topology.c | 10 ++++++ > include/linux/acpi.h | 5 +++ > include/linux/arch_topology.h | 5 +++ > include/linux/topology.h | 6 ++++ > 8 files changed, 124 insertions(+), 4 deletions(-) > > diff --git a/Documentation/admin-guide/cputopology.rst b/Documentation/admin-guide/cputopology.rst > index b90dafc..f9d3745 100644 > --- a/Documentation/admin-guide/cputopology.rst > +++ b/Documentation/admin-guide/cputopology.rst > @@ -24,6 +24,12 @@ core_id: > identifier (rather than the kernel's). The actual value is > architecture and platform dependent. > > +cluster_id: > + > + the Cluster ID of cpuX. Typically it is the hardware platform's > + identifier (rather than the kernel's). The actual value is > + architecture and platform dependent. > + > book_id: > > the book ID of cpuX. Typically it is the hardware platform's > @@ -56,6 +62,14 @@ package_cpus_list: > human-readable list of CPUs sharing the same physical_package_id. > (deprecated name: "core_siblings_list") > > +cluster_cpus: > + > + internal kernel map of CPUs within the same cluster. > + > +cluster_cpus_list: > + > + human-readable list of CPUs within the same cluster. > + > die_cpus: > > internal kernel map of CPUs within the same die. > @@ -96,11 +110,13 @@ these macros in include/asm-XXX/topology.h:: > > #define topology_physical_package_id(cpu) > #define topology_die_id(cpu) > + #define topology_cluster_id(cpu) > #define topology_core_id(cpu) > #define topology_book_id(cpu) > #define topology_drawer_id(cpu) > #define topology_sibling_cpumask(cpu) > #define topology_core_cpumask(cpu) > + #define topology_cluster_cpumask(cpu) > #define topology_die_cpumask(cpu) > #define topology_book_cpumask(cpu) > #define topology_drawer_cpumask(cpu) > @@ -116,10 +132,12 @@ not defined by include/asm-XXX/topology.h: > > 1) topology_physical_package_id: -1 > 2) topology_die_id: -1 > -3) topology_core_id: 0 > -4) topology_sibling_cpumask: just the given CPU > -5) topology_core_cpumask: just the given CPU > -6) topology_die_cpumask: just the given CPU > +3) topology_cluster_id: -1 > +4) topology_core_id: 0 > +5) topology_sibling_cpumask: just the given CPU > +6) topology_core_cpumask: just the given CPU > +7) topology_cluster_cpumask: just the given CPU > +8) topology_die_cpumask: just the given CPU > > For architectures that don't support books (CONFIG_SCHED_BOOK) there are no > default definitions for topology_book_id() and topology_book_cpumask(). > diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c > index f6faa69..fe076b3 100644 > --- a/arch/arm64/kernel/topology.c > +++ b/arch/arm64/kernel/topology.c > @@ -103,6 +103,8 @@ int __init parse_acpi_topology(void) > cpu_topology[cpu].thread_id = -1; > cpu_topology[cpu].core_id = topology_id; > } > + topology_id = find_acpi_cpu_topology_cluster(cpu); > + cpu_topology[cpu].cluster_id = topology_id; > topology_id = find_acpi_cpu_topology_package(cpu); > cpu_topology[cpu].package_id = topology_id; > > diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c > index 4ae9335..8646a93 100644 > --- a/drivers/acpi/pptt.c > +++ b/drivers/acpi/pptt.c > @@ -737,6 +737,66 @@ int find_acpi_cpu_topology_package(unsigned int cpu) > } > > /** > + * find_acpi_cpu_topology_cluster() - Determine a unique CPU cluster value > + * @cpu: Kernel logical CPU number > + * > + * Determine a topology unique cluster ID for the given CPU/thread. > + * This ID can then be used to group peers, which will have matching ids. > + * > + * The cluster, if present is the level of topology above CPUs. In a > + * multi-thread CPU, it will be the level above the CPU, not the thread. > + * It may not exist in single CPU systems. In simple multi-CPU systems, > + * it may be equal to the package topology level. > + * > + * Return: -ENOENT if the PPTT doesn't exist, the CPU cannot be found > + * or there is no toplogy level above the CPU.. > + * Otherwise returns a value which represents the package for this CPU. > + */ > + > +int find_acpi_cpu_topology_cluster(unsigned int cpu) > +{ > + struct acpi_table_header *table; > + acpi_status status; > + struct acpi_pptt_processor *cpu_node, *cluster_node; > + int retval; > + int is_thread; > + > + status = acpi_get_table(ACPI_SIG_PPTT, 0, &table); > + if (ACPI_FAILURE(status)) { > + acpi_pptt_warn_missing(); > + return -ENOENT; > + } > + cpu_node = acpi_find_processor_node(table, cpu); The second argument of acpi_find_processor_node() expects ACPI Processor ID, not the logical cpu number. How about the following? acpi_cpu_id = get_acpi_id_for_cpu(cpu); cpu_node = acpi_find_processor_node(table, acpi_cpu_id); Thanks, Masa > + if (cpu_node == NULL || !cpu_node->parent) { > + retval = -ENOENT; > + goto put_table; > + } > + > + is_thread = cpu_node->flags & ACPI_PPTT_ACPI_PROCESSOR_IS_THREAD; > + cluster_node = fetch_pptt_node(table, cpu_node->parent); > + if (cluster_node == NULL) { > + retval = -ENOENT; > + goto put_table; > + } > + if (is_thread) { > + if (!cluster_node->parent) { > + retval = -ENOENT; > + goto put_table; > + } > + cluster_node = fetch_pptt_node(table, cluster_node->parent); > + if (cluster_node == NULL) { > + retval = -ENOENT; > + goto put_table; > + } > + } > + retval = ACPI_PTR_DIFF(cluster_node, table); > +put_table: > + acpi_put_table(table); > + > + return retval; > +} > + > +/** > * find_acpi_cpu_topology_hetero_id() - Get a core architecture tag > * @cpu: Kernel logical CPU number > * > diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c > index de8587c..3079232 100644 > --- a/drivers/base/arch_topology.c > +++ b/drivers/base/arch_topology.c > @@ -506,6 +506,11 @@ const struct cpumask *cpu_coregroup_mask(int cpu) > return core_mask; > } > > +const struct cpumask *cpu_clustergroup_mask(int cpu) > +{ > + return &cpu_topology[cpu].cluster_sibling; > +} > + > void update_siblings_masks(unsigned int cpuid) > { > struct cpu_topology *cpu_topo, *cpuid_topo = &cpu_topology[cpuid]; > @@ -523,6 +528,11 @@ void update_siblings_masks(unsigned int cpuid) > if (cpuid_topo->package_id != cpu_topo->package_id) > continue; > > + if (cpuid_topo->cluster_id == cpu_topo->cluster_id) { > + cpumask_set_cpu(cpu, &cpuid_topo->cluster_sibling); > + cpumask_set_cpu(cpuid, &cpu_topo->cluster_sibling); > + } > + > cpumask_set_cpu(cpuid, &cpu_topo->core_sibling); > cpumask_set_cpu(cpu, &cpuid_topo->core_sibling); > > @@ -541,6 +551,9 @@ static void clear_cpu_topology(int cpu) > cpumask_clear(&cpu_topo->llc_sibling); > cpumask_set_cpu(cpu, &cpu_topo->llc_sibling); > > + cpumask_clear(&cpu_topo->cluster_sibling); > + cpumask_set_cpu(cpu, &cpu_topo->cluster_sibling); > + > cpumask_clear(&cpu_topo->core_sibling); > cpumask_set_cpu(cpu, &cpu_topo->core_sibling); > cpumask_clear(&cpu_topo->thread_sibling); > @@ -571,6 +584,7 @@ void remove_cpu_topology(unsigned int cpu) > cpumask_clear_cpu(cpu, topology_core_cpumask(sibling)); > for_each_cpu(sibling, topology_sibling_cpumask(cpu)) > cpumask_clear_cpu(cpu, topology_sibling_cpumask(sibling)); > + > for_each_cpu(sibling, topology_llc_cpumask(cpu)) > cpumask_clear_cpu(cpu, topology_llc_cpumask(sibling)); > > diff --git a/drivers/base/topology.c b/drivers/base/topology.c > index 4d254fc..7157ac0 100644 > --- a/drivers/base/topology.c > +++ b/drivers/base/topology.c > @@ -46,6 +46,9 @@ static DEVICE_ATTR_RO(physical_package_id); > define_id_show_func(die_id); > static DEVICE_ATTR_RO(die_id); > > +define_id_show_func(cluster_id); > +static DEVICE_ATTR_RO(cluster_id); > + > define_id_show_func(core_id); > static DEVICE_ATTR_RO(core_id); > > @@ -61,6 +64,10 @@ define_siblings_show_func(core_siblings, core_cpumask); > static DEVICE_ATTR_RO(core_siblings); > static DEVICE_ATTR_RO(core_siblings_list); > > +define_siblings_show_func(cluster_cpus, cluster_cpumask); > +static DEVICE_ATTR_RO(cluster_cpus); > +static DEVICE_ATTR_RO(cluster_cpus_list); > + > define_siblings_show_func(die_cpus, die_cpumask); > static DEVICE_ATTR_RO(die_cpus); > static DEVICE_ATTR_RO(die_cpus_list); > @@ -88,6 +95,7 @@ static DEVICE_ATTR_RO(drawer_siblings_list); > static struct attribute *default_attrs[] = { > &dev_attr_physical_package_id.attr, > &dev_attr_die_id.attr, > + &dev_attr_cluster_id.attr, > &dev_attr_core_id.attr, > &dev_attr_thread_siblings.attr, > &dev_attr_thread_siblings_list.attr, > @@ -95,6 +103,8 @@ static struct attribute *default_attrs[] = { > &dev_attr_core_cpus_list.attr, > &dev_attr_core_siblings.attr, > &dev_attr_core_siblings_list.attr, > + &dev_attr_cluster_cpus.attr, > + &dev_attr_cluster_cpus_list.attr, > &dev_attr_die_cpus.attr, > &dev_attr_die_cpus_list.attr, > &dev_attr_package_cpus.attr, > diff --git a/include/linux/acpi.h b/include/linux/acpi.h > index 2630c2e..8f603cd 100644 > --- a/include/linux/acpi.h > +++ b/include/linux/acpi.h > @@ -1325,6 +1325,7 @@ static inline int lpit_read_residency_count_address(u64 *address) > #ifdef CONFIG_ACPI_PPTT > int acpi_pptt_cpu_is_thread(unsigned int cpu); > int find_acpi_cpu_topology(unsigned int cpu, int level); > +int find_acpi_cpu_topology_cluster(unsigned int cpu); > int find_acpi_cpu_topology_package(unsigned int cpu); > int find_acpi_cpu_topology_hetero_id(unsigned int cpu); > int find_acpi_cpu_cache_topology(unsigned int cpu, int level); > @@ -1337,6 +1338,10 @@ static inline int find_acpi_cpu_topology(unsigned int cpu, int level) > { > return -EINVAL; > } > +static inline int find_acpi_cpu_topology_cluster(unsigned int cpu) > +{ > + return -EINVAL; > +} > static inline int find_acpi_cpu_topology_package(unsigned int cpu) > { > return -EINVAL; > diff --git a/include/linux/arch_topology.h b/include/linux/arch_topology.h > index 0f6cd6b..987c7ea 100644 > --- a/include/linux/arch_topology.h > +++ b/include/linux/arch_topology.h > @@ -49,10 +49,12 @@ void topology_set_thermal_pressure(const struct cpumask *cpus, > struct cpu_topology { > int thread_id; > int core_id; > + int cluster_id; > int package_id; > int llc_id; > cpumask_t thread_sibling; > cpumask_t core_sibling; > + cpumask_t cluster_sibling; > cpumask_t llc_sibling; > }; > > @@ -60,13 +62,16 @@ struct cpu_topology { > extern struct cpu_topology cpu_topology[NR_CPUS]; > > #define topology_physical_package_id(cpu) (cpu_topology[cpu].package_id) > +#define topology_cluster_id(cpu) (cpu_topology[cpu].cluster_id) > #define topology_core_id(cpu) (cpu_topology[cpu].core_id) > #define topology_core_cpumask(cpu) (&cpu_topology[cpu].core_sibling) > #define topology_sibling_cpumask(cpu) (&cpu_topology[cpu].thread_sibling) > +#define topology_cluster_cpumask(cpu) (&cpu_topology[cpu].cluster_sibling) > #define topology_llc_cpumask(cpu) (&cpu_topology[cpu].llc_sibling) > void init_cpu_topology(void); > void store_cpu_topology(unsigned int cpuid); > const struct cpumask *cpu_coregroup_mask(int cpu); > +const struct cpumask *cpu_clustergroup_mask(int cpu); > void update_siblings_masks(unsigned int cpu); > void remove_cpu_topology(unsigned int cpuid); > void reset_cpu_topology(void); > diff --git a/include/linux/topology.h b/include/linux/topology.h > index ad03df1..bf2cc3c 100644 > --- a/include/linux/topology.h > +++ b/include/linux/topology.h > @@ -185,6 +185,9 @@ static inline int cpu_to_mem(int cpu) > #ifndef topology_die_id > #define topology_die_id(cpu) ((void)(cpu), -1) > #endif > +#ifndef topology_cluster_id > +#define topology_cluster_id(cpu) ((void)(cpu), -1) > +#endif > #ifndef topology_core_id > #define topology_core_id(cpu) ((void)(cpu), 0) > #endif > @@ -194,6 +197,9 @@ static inline int cpu_to_mem(int cpu) > #ifndef topology_core_cpumask > #define topology_core_cpumask(cpu) cpumask_of(cpu) > #endif > +#ifndef topology_cluster_cpumask > +#define topology_cluster_cpumask(cpu) cpumask_of(cpu) > +#endif > #ifndef topology_die_cpumask > #define topology_die_cpumask(cpu) cpumask_of(cpu) > #endif > -- > 2.7.4 >
