| Message ID | abaea3bd2aa89c7c9f284e3a7beabb865d8e1050.1530867876.git.ego@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
| Series | powerpc: Detection and scheduler optimization for POWER9 bigcore | expand |
On Fri, Jul 06, 2018 at 02:35:48PM +0530, Gautham R. Shenoy wrote: > From: "Gautham R. Shenoy" <ego@linux.vnet.ibm.com> > > On IBM POWER9, the device tree exposes a property array identifed by > "ibm,thread-groups" which will indicate which groups of threads share a > particular set of resources. > > As of today we only have one form of grouping identifying the group of > threads in the core that share the L1 cache, translation cache and > instruction data flow. > > This patch defines the helper function to parse the contents of > "ibm,thread-groups" and a new structure to contain the parsed output. > > The patch also creates the sysfs file named "small_core_siblings" that > returns the physical ids of the threads in the core that share the L1 > cache, translation cache and instruction data flow. > > Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com> > --- > Documentation/ABI/testing/sysfs-devices-system-cpu | 8 ++ > arch/powerpc/include/asm/cputhreads.h | 22 +++ > arch/powerpc/kernel/setup-common.c | 154 +++++++++++++++++++++ > arch/powerpc/kernel/sysfs.c | 35 +++++ > 4 files changed, 219 insertions(+) > > diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu > index 9c5e7732..62f24de 100644 > --- a/Documentation/ABI/testing/sysfs-devices-system-cpu > +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu > @@ -487,3 +487,11 @@ Description: Information about CPU vulnerabilities > "Not affected" CPU is not affected by the vulnerability > "Vulnerable" CPU is affected and no mitigation in effect > "Mitigation: $M" CPU is affected and mitigation $M is in effect > + > +What: /sys/devices/system/cpu/cpu[0-9]+/small_core_siblings > +Date: 05-Jul-2018 > +KernelVersion: v4.18.0 > +Contact: Gautham R. Shenoy <ego@linux.vnet.ibm.com> > +Description: List of Physical ids of CPUs which share the the L1 cache, > + translation cache and instruction data-flow with this CPU. What about this? Description: List of physical CPU IDs that share a common L1 cache, translation cache and instruction data flow with this CPU. Or perhaps just remove the extra "the". > +Values: Comma separated list of decimal integers. > diff --git a/arch/powerpc/include/asm/cputhreads.h b/arch/powerpc/include/asm/cputhreads.h > index d71a909..33226d7 100644 > --- a/arch/powerpc/include/asm/cputhreads.h > +++ b/arch/powerpc/include/asm/cputhreads.h > @@ -23,11 +23,13 @@ > extern int threads_per_core; > extern int threads_per_subcore; > extern int threads_shift; > +extern bool has_big_cores; > extern cpumask_t threads_core_mask; > #else > #define threads_per_core 1 > #define threads_per_subcore 1 > #define threads_shift 0 > +#define has_big_cores 0 > #define threads_core_mask (*get_cpu_mask(0)) > #endif > > @@ -69,12 +71,32 @@ static inline cpumask_t cpu_online_cores_map(void) > return cpu_thread_mask_to_cores(cpu_online_mask); > } > > +#define MAX_THREAD_LIST_SIZE 8 > +struct thread_groups { > + unsigned int property; > + unsigned int nr_groups; > + unsigned int threads_per_group; > + unsigned int thread_list[MAX_THREAD_LIST_SIZE]; > +}; > + > #ifdef CONFIG_SMP > int cpu_core_index_of_thread(int cpu); > int cpu_first_thread_of_core(int core); > +int parse_thread_groups(struct device_node *dn, struct thread_groups *tg); > +int get_cpu_thread_group_start(int cpu, struct thread_groups *tg); > #else > static inline int cpu_core_index_of_thread(int cpu) { return cpu; } > static inline int cpu_first_thread_of_core(int core) { return core; } > +static inline int parse_thread_groups(struct device_node *dn, > + struct thread_groups *tg) > +{ > + return -ENODATA; > +} > + > +static inline int get_cpu_thread_group_start(int cpu, struct thread_groups *tg) > +{ > + return -1; > +} > #endif > > static inline int cpu_thread_in_core(int cpu) > diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c > index 40b44bb..989edc1 100644 > --- a/arch/powerpc/kernel/setup-common.c > +++ b/arch/powerpc/kernel/setup-common.c > @@ -402,10 +402,12 @@ void __init check_for_initrd(void) > #ifdef CONFIG_SMP > > int threads_per_core, threads_per_subcore, threads_shift; > +bool has_big_cores; > cpumask_t threads_core_mask; > EXPORT_SYMBOL_GPL(threads_per_core); > EXPORT_SYMBOL_GPL(threads_per_subcore); > EXPORT_SYMBOL_GPL(threads_shift); > +EXPORT_SYMBOL_GPL(has_big_cores); > EXPORT_SYMBOL_GPL(threads_core_mask); > > static void __init cpu_init_thread_core_maps(int tpc) > @@ -433,6 +435,152 @@ static void __init cpu_init_thread_core_maps(int tpc) > > u32 *cpu_to_phys_id = NULL; > > +/* > + * parse_thread_groups: Parses the "ibm,thread-groups" device tree > + * property for the CPU device node @dn and stores > + * the parsed output in the thread_groups > + * structure @tg. > + * > + * @dn: The device node of the CPU device. > + * @tg: Pointer to a thread group structure into which the parsed > + * output of "ibm,thread-groups" is stored. > + * > + * ibm,thread-groups[0..N-1] array defines which group of threads in > + * the CPU-device node can be grouped together based on the property. > + * > + * ibm,thread-groups[0] tells us the property based on which the > + * threads are being grouped together. If this value is 1, it implies > + * that the threads in the same group share L1, translation cache. > + * > + * ibm,thread-groups[1] tells us how many such thread groups exist. > + * > + * ibm,thread-groups[2] tells us the number of threads in each such > + * group. > + * > + * ibm,thread-groups[3..N-1] is the list of threads identified by > + * "ibm,ppc-interrupt-server#s" arranged as per their membership in > + * the grouping. > + * > + * Example: If ibm,thread-groups = [1,2,4,5,6,7,8,9,10,11,12] it > + * implies that there are 2 groups of 4 threads each, where each group > + * of threads share L1, translation cache. > + * > + * The "ibm,ppc-interrupt-server#s" of the first group is {5,6,7,8} > + * and the "ibm,ppc-interrupt-server#s" of the second group is {9, 10, > + * 11, 12} structure > + * > + * Returns 0 on success, -EINVAL if the property does not exist, > + * -ENODATA if property does not have a value, and -EOVERFLOW if the > + * property data isn't large enough. > + */ > +int parse_thread_groups(struct device_node *dn, > + struct thread_groups *tg) > +{ > + unsigned int nr_groups, threads_per_group, property; > + int i; > + u32 thread_group_array[3 + MAX_THREAD_LIST_SIZE]; > + u32 *thread_list; > + size_t total_threads; > + int ret; > + > + ret = of_property_read_u32_array(dn, "ibm,thread-groups", > + thread_group_array, 3); > + > + if (ret) > + goto out_err; > + > + property = thread_group_array[0]; > + nr_groups = thread_group_array[1]; > + threads_per_group = thread_group_array[2]; > + total_threads = nr_groups * threads_per_group; > + > + ret = of_property_read_u32_array(dn, "ibm,thread-groups", > + thread_group_array, > + 3 + total_threads); > + if (ret) > + goto out_err; > + > + thread_list = &thread_group_array[3]; > + > + for (i = 0 ; i < total_threads; i++) > + tg->thread_list[i] = thread_list[i]; > + > + tg->property = property; > + tg->nr_groups = nr_groups; > + tg->threads_per_group = threads_per_group; > + > + return 0; > +out_err: > + tg->property = 0; > + tg->nr_groups = 0; > + tg->threads_per_group = 0; > + return ret; > +} > + > +/* > + * dt_has_big_core : Parses the device tree property > + * "ibm,thread-groups" for device node pointed by @dn > + * and stores the parsed output in the structure > + * pointed to by @tg. Then checks if the output in > + * @tg corresponds to a big-core. > + * > + * @dn: Device node pointer of the CPU node being checked for a > + * big-core. > + * @tg: Pointer to thread_groups struct in which parsed output of > + * "ibm,thread-groups" is recorded. > + * > + * Returns true if the @dn points to a big-core. > + * Returns false if there is an error in parsing "ibm,thread-groups" > + * or the parsed output doesn't correspond to a big-core. > + */ > +static inline bool dt_has_big_core(struct device_node *dn, > + struct thread_groups *tg) > +{ > + if (parse_thread_groups(dn, tg)) > + return false; > + > + if (tg->property != 1) > + return false; > + > + if (tg->nr_groups < 1) > + return false; > + > + return true; > +} > + > +/* > + * get_cpu_thread_group_start : Searches the thread group in tg->thread_list > + * that @cpu belongs to. > + * > + * @cpu : The logical CPU whose thread group is being searched. > + * @tg : The thread-group structure of the CPU node which @cpu belongs > + * to. > + * > + * Returns the index to tg->thread_list that points to the the start > + * of the thread_group that @cpu belongs to. > + * > + * Returns -1 if cpu doesn't belong to any of the groups pointed to by > + * tg->thread_list. > + */ > +int get_cpu_thread_group_start(int cpu, struct thread_groups *tg) > +{ > + int hw_cpu_id = get_hard_smp_processor_id(cpu); > + int i, j; > + > + for (i = 0; i < tg->nr_groups; i++) { > + int group_start = i * tg->threads_per_group; > + > + for (j = 0; j < tg->threads_per_group; j++) { > + int idx = group_start + j; > + > + if (tg->thread_list[idx] == hw_cpu_id) > + return group_start; > + } > + } > + > + return -1; > +} > + > /** > * setup_cpu_maps - initialize the following cpu maps: > * cpu_possible_mask > @@ -457,6 +605,7 @@ void __init smp_setup_cpu_maps(void) > int cpu = 0; > int nthreads = 1; > > + has_big_cores = true; > DBG("smp_setup_cpu_maps()\n"); > > cpu_to_phys_id = __va(memblock_alloc(nr_cpu_ids * sizeof(u32), > @@ -467,6 +616,7 @@ void __init smp_setup_cpu_maps(void) > const __be32 *intserv; > __be32 cpu_be; > int j, len; > + struct thread_groups tg; > > DBG(" * %pOF...\n", dn); > > @@ -505,6 +655,10 @@ void __init smp_setup_cpu_maps(void) > cpu++; > } > > + if (has_big_cores && !dt_has_big_core(dn, &tg)) { > + has_big_cores = false; > + } > + > if (cpu >= nr_cpu_ids) { > of_node_put(dn); > break; > diff --git a/arch/powerpc/kernel/sysfs.c b/arch/powerpc/kernel/sysfs.c > index 755dc98..f5717de 100644 > --- a/arch/powerpc/kernel/sysfs.c > +++ b/arch/powerpc/kernel/sysfs.c > @@ -18,6 +18,7 @@ > #include <asm/smp.h> > #include <asm/pmc.h> > #include <asm/firmware.h> > +#include <asm/cputhreads.h> > > #include "cacheinfo.h" > #include "setup.h" > @@ -1025,6 +1026,33 @@ static ssize_t show_physical_id(struct device *dev, > } > static DEVICE_ATTR(physical_id, 0444, show_physical_id, NULL); > > +static ssize_t show_small_core_siblings(struct device *dev, > + struct device_attribute *attr, > + char *buf) > +{ Interesting enough, checkpatch.pl warned about this function name: WARNING: Consider renaming function(s) 'show_small_core_siblings' to 'small_core_siblings_show' #354: FILE: arch/powerpc/kernel/sysfs.c:1053: +} > + struct cpu *cpu = container_of(dev, struct cpu, dev); > + struct device_node *dn = of_get_cpu_node(cpu->dev.id, NULL); > + struct thread_groups tg; > + int i, j; > + ssize_t ret = 0; > + > + if (parse_thread_groups(dn, &tg)) > + return -ENODATA; > + > + i = get_cpu_thread_group_start(cpu->dev.id, &tg); > + > + if (i == -1) > + return -ENODATA; > + > + for (j = 0; j < tg.threads_per_group - 1; j++) > + ret += sprintf(buf + ret, "%d,", tg.thread_list[i + j]); > + > + ret += sprintf(buf + ret, "%d\n", tg.thread_list[i + j]); > + > + return ret; > +} > +static DEVICE_ATTR(small_core_siblings, 0444, show_small_core_siblings, NULL); > + > static int __init topology_init(void) > { > int cpu, r; > @@ -1048,6 +1076,13 @@ static int __init topology_init(void) > register_cpu(c, cpu); > > device_create_file(&c->dev, &dev_attr_physical_id); > + > + if (has_big_cores) { > + const struct device_attribute *attr = > + &dev_attr_small_core_siblings; > + > + device_create_file(&c->dev, attr); > + } > } > } > r = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "powerpc/topology:online", > -- > 1.9.4 >
On Sun, 2018-07-08 at 13:03 -0300, Murilo Opsfelder Araujo wrote: > On Fri, Jul 06, 2018 at 02:35:48PM +0530, Gautham R. Shenoy wrote: > > From: "Gautham R. Shenoy" <ego@linux.vnet.ibm.com> > > > > On IBM POWER9, the device tree exposes a property array identifed by > > "ibm,thread-groups" which will indicate which groups of threads share a > > particular set of resources. [] > > diff --git a/arch/powerpc/kernel/sysfs.c b/arch/powerpc/kernel/sysfs.c [] > > @@ -1025,6 +1026,33 @@ static ssize_t show_physical_id(struct device *dev, > > } > > static DEVICE_ATTR(physical_id, 0444, show_physical_id, NULL); > > > > +static ssize_t show_small_core_siblings(struct device *dev, > > + struct device_attribute *attr, > > + char *buf) > > +{ > > Interesting enough, checkpatch.pl warned about this function name: > > WARNING: Consider renaming function(s) 'show_small_core_siblings' to 'small_core_siblings_show' > #354: FILE: arch/powerpc/kernel/sysfs.c:1053: > +} It's to allow the DEVICE_ATTR below to be renamed to DEVICE_ATTR_RO > > +static DEVICE_ATTR(small_core_siblings, 0444, show_small_core_siblings, NULL); So this becomes DEVICE_ATTR_RO(small_core_siblings)
Hello Murilo, On Sun, Jul 08, 2018 at 01:03:34PM -0300, Murilo Opsfelder Araujo wrote: > On Fri, Jul 06, 2018 at 02:35:48PM +0530, Gautham R. Shenoy wrote: > > From: "Gautham R. Shenoy" <ego@linux.vnet.ibm.com> > > > > On IBM POWER9, the device tree exposes a property array identifed by > > "ibm,thread-groups" which will indicate which groups of threads share a > > particular set of resources. > > > > As of today we only have one form of grouping identifying the group of > > threads in the core that share the L1 cache, translation cache and > > instruction data flow. > > > > This patch defines the helper function to parse the contents of > > "ibm,thread-groups" and a new structure to contain the parsed output. > > > > The patch also creates the sysfs file named "small_core_siblings" that > > returns the physical ids of the threads in the core that share the L1 > > cache, translation cache and instruction data flow. > > > > Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com> > > --- > > Documentation/ABI/testing/sysfs-devices-system-cpu | 8 ++ > > arch/powerpc/include/asm/cputhreads.h | 22 +++ > > arch/powerpc/kernel/setup-common.c | 154 +++++++++++++++++++++ > > arch/powerpc/kernel/sysfs.c | 35 +++++ > > 4 files changed, 219 insertions(+) > > > > diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu > > index 9c5e7732..62f24de 100644 > > --- a/Documentation/ABI/testing/sysfs-devices-system-cpu > > +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu > > @@ -487,3 +487,11 @@ Description: Information about CPU vulnerabilities > > "Not affected" CPU is not affected by the vulnerability > > "Vulnerable" CPU is affected and no mitigation in effect > > "Mitigation: $M" CPU is affected and mitigation $M is in effect > > + > > +What: /sys/devices/system/cpu/cpu[0-9]+/small_core_siblings > > +Date: 05-Jul-2018 > > +KernelVersion: v4.18.0 > > +Contact: Gautham R. Shenoy <ego@linux.vnet.ibm.com> > > +Description: List of Physical ids of CPUs which share the the L1 cache, > > + translation cache and instruction data-flow with this CPU. > > What about this? > > Description: List of physical CPU IDs that share a common L1 cache, > translation cache and instruction data flow with this CPU. > > Or perhaps just remove the extra "the". Oops! Will remove the extra "the". Thanks for spotting it. > > > +Values: Comma separated list of decimal integers. > > diff --git a/arch/powerpc/include/asm/cputhreads.h b/arch/powerpc/include/asm/cputhreads.h > > index d71a909..33226d7 100644 > > --- a/arch/powerpc/include/asm/cputhreads.h [..snip..] > > diff --git a/arch/powerpc/kernel/sysfs.c b/arch/powerpc/kernel/sysfs.c > > index 755dc98..f5717de 100644 > > --- a/arch/powerpc/kernel/sysfs.c > > +++ b/arch/powerpc/kernel/sysfs.c > > @@ -18,6 +18,7 @@ > > #include <asm/smp.h> > > #include <asm/pmc.h> > > #include <asm/firmware.h> > > +#include <asm/cputhreads.h> > > > > #include "cacheinfo.h" > > #include "setup.h" > > @@ -1025,6 +1026,33 @@ static ssize_t show_physical_id(struct device *dev, > > } > > static DEVICE_ATTR(physical_id, 0444, show_physical_id, NULL); > > > > +static ssize_t show_small_core_siblings(struct device *dev, > > + struct device_attribute *attr, > > + char *buf) > > +{ > > Interesting enough, checkpatch.pl warned about this function name: > > WARNING: Consider renaming function(s) 'show_small_core_siblings' to 'small_core_siblings_show' > #354: FILE: arch/powerpc/kernel/sysfs.c:1053: > +} Yes I kept it despite the warning, as doing otherwise would introduce inconsistency with the way the remaining functions are named in the file. If Michael Ellerman is ok, I can send a file converting all these sysfs calls to use DEVICE_ATTR_RO/RW, which will require renaming all the other functions to XXX_show(). > > > + struct cpu *cpu = container_of(dev, struct cpu, dev); > > + struct device_node *dn = of_get_cpu_node(cpu->dev.id, NULL); > > + struct thread_groups tg; > > + int i, j; > > + ssize_t ret = 0; > > + > > + if (parse_thread_groups(dn, &tg)) > > + return -ENODATA; > > + > > + i = get_cpu_thread_group_start(cpu->dev.id, &tg); > > + > > + if (i == -1) > > + return -ENODATA; > > + > > + for (j = 0; j < tg.threads_per_group - 1; j++) > > + ret += sprintf(buf + ret, "%d,", tg.thread_list[i + j]); > > + > > + ret += sprintf(buf + ret, "%d\n", tg.thread_list[i + j]); > > + > > + return ret; > > +} > > +static DEVICE_ATTR(small_core_siblings, 0444, show_small_core_siblings, NULL); > > + > > static int __init topology_init(void) > > { > > int cpu, r; > > @@ -1048,6 +1076,13 @@ static int __init topology_init(void) > > register_cpu(c, cpu); > > > > device_create_file(&c->dev, &dev_attr_physical_id); > > + > > + if (has_big_cores) { > > + const struct device_attribute *attr = > > + &dev_attr_small_core_siblings; > > + > > + device_create_file(&c->dev, attr); > > + } > > } > > } > > r = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "powerpc/topology:online", > > -- > > 1.9.4 > > > > -- > Murilo
diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu index 9c5e7732..62f24de 100644 --- a/Documentation/ABI/testing/sysfs-devices-system-cpu +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu @@ -487,3 +487,11 @@ Description: Information about CPU vulnerabilities "Not affected" CPU is not affected by the vulnerability "Vulnerable" CPU is affected and no mitigation in effect "Mitigation: $M" CPU is affected and mitigation $M is in effect + +What: /sys/devices/system/cpu/cpu[0-9]+/small_core_siblings +Date: 05-Jul-2018 +KernelVersion: v4.18.0 +Contact: Gautham R. Shenoy <ego@linux.vnet.ibm.com> +Description: List of Physical ids of CPUs which share the the L1 cache, + translation cache and instruction data-flow with this CPU. +Values: Comma separated list of decimal integers. diff --git a/arch/powerpc/include/asm/cputhreads.h b/arch/powerpc/include/asm/cputhreads.h index d71a909..33226d7 100644 --- a/arch/powerpc/include/asm/cputhreads.h +++ b/arch/powerpc/include/asm/cputhreads.h @@ -23,11 +23,13 @@ extern int threads_per_core; extern int threads_per_subcore; extern int threads_shift; +extern bool has_big_cores; extern cpumask_t threads_core_mask; #else #define threads_per_core 1 #define threads_per_subcore 1 #define threads_shift 0 +#define has_big_cores 0 #define threads_core_mask (*get_cpu_mask(0)) #endif @@ -69,12 +71,32 @@ static inline cpumask_t cpu_online_cores_map(void) return cpu_thread_mask_to_cores(cpu_online_mask); } +#define MAX_THREAD_LIST_SIZE 8 +struct thread_groups { + unsigned int property; + unsigned int nr_groups; + unsigned int threads_per_group; + unsigned int thread_list[MAX_THREAD_LIST_SIZE]; +}; + #ifdef CONFIG_SMP int cpu_core_index_of_thread(int cpu); int cpu_first_thread_of_core(int core); +int parse_thread_groups(struct device_node *dn, struct thread_groups *tg); +int get_cpu_thread_group_start(int cpu, struct thread_groups *tg); #else static inline int cpu_core_index_of_thread(int cpu) { return cpu; } static inline int cpu_first_thread_of_core(int core) { return core; } +static inline int parse_thread_groups(struct device_node *dn, + struct thread_groups *tg) +{ + return -ENODATA; +} + +static inline int get_cpu_thread_group_start(int cpu, struct thread_groups *tg) +{ + return -1; +} #endif static inline int cpu_thread_in_core(int cpu) diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c index 40b44bb..989edc1 100644 --- a/arch/powerpc/kernel/setup-common.c +++ b/arch/powerpc/kernel/setup-common.c @@ -402,10 +402,12 @@ void __init check_for_initrd(void) #ifdef CONFIG_SMP int threads_per_core, threads_per_subcore, threads_shift; +bool has_big_cores; cpumask_t threads_core_mask; EXPORT_SYMBOL_GPL(threads_per_core); EXPORT_SYMBOL_GPL(threads_per_subcore); EXPORT_SYMBOL_GPL(threads_shift); +EXPORT_SYMBOL_GPL(has_big_cores); EXPORT_SYMBOL_GPL(threads_core_mask); static void __init cpu_init_thread_core_maps(int tpc) @@ -433,6 +435,152 @@ static void __init cpu_init_thread_core_maps(int tpc) u32 *cpu_to_phys_id = NULL; +/* + * parse_thread_groups: Parses the "ibm,thread-groups" device tree + * property for the CPU device node @dn and stores + * the parsed output in the thread_groups + * structure @tg. + * + * @dn: The device node of the CPU device. + * @tg: Pointer to a thread group structure into which the parsed + * output of "ibm,thread-groups" is stored. + * + * ibm,thread-groups[0..N-1] array defines which group of threads in + * the CPU-device node can be grouped together based on the property. + * + * ibm,thread-groups[0] tells us the property based on which the + * threads are being grouped together. If this value is 1, it implies + * that the threads in the same group share L1, translation cache. + * + * ibm,thread-groups[1] tells us how many such thread groups exist. + * + * ibm,thread-groups[2] tells us the number of threads in each such + * group. + * + * ibm,thread-groups[3..N-1] is the list of threads identified by + * "ibm,ppc-interrupt-server#s" arranged as per their membership in + * the grouping. + * + * Example: If ibm,thread-groups = [1,2,4,5,6,7,8,9,10,11,12] it + * implies that there are 2 groups of 4 threads each, where each group + * of threads share L1, translation cache. + * + * The "ibm,ppc-interrupt-server#s" of the first group is {5,6,7,8} + * and the "ibm,ppc-interrupt-server#s" of the second group is {9, 10, + * 11, 12} structure + * + * Returns 0 on success, -EINVAL if the property does not exist, + * -ENODATA if property does not have a value, and -EOVERFLOW if the + * property data isn't large enough. + */ +int parse_thread_groups(struct device_node *dn, + struct thread_groups *tg) +{ + unsigned int nr_groups, threads_per_group, property; + int i; + u32 thread_group_array[3 + MAX_THREAD_LIST_SIZE]; + u32 *thread_list; + size_t total_threads; + int ret; + + ret = of_property_read_u32_array(dn, "ibm,thread-groups", + thread_group_array, 3); + + if (ret) + goto out_err; + + property = thread_group_array[0]; + nr_groups = thread_group_array[1]; + threads_per_group = thread_group_array[2]; + total_threads = nr_groups * threads_per_group; + + ret = of_property_read_u32_array(dn, "ibm,thread-groups", + thread_group_array, + 3 + total_threads); + if (ret) + goto out_err; + + thread_list = &thread_group_array[3]; + + for (i = 0 ; i < total_threads; i++) + tg->thread_list[i] = thread_list[i]; + + tg->property = property; + tg->nr_groups = nr_groups; + tg->threads_per_group = threads_per_group; + + return 0; +out_err: + tg->property = 0; + tg->nr_groups = 0; + tg->threads_per_group = 0; + return ret; +} + +/* + * dt_has_big_core : Parses the device tree property + * "ibm,thread-groups" for device node pointed by @dn + * and stores the parsed output in the structure + * pointed to by @tg. Then checks if the output in + * @tg corresponds to a big-core. + * + * @dn: Device node pointer of the CPU node being checked for a + * big-core. + * @tg: Pointer to thread_groups struct in which parsed output of + * "ibm,thread-groups" is recorded. + * + * Returns true if the @dn points to a big-core. + * Returns false if there is an error in parsing "ibm,thread-groups" + * or the parsed output doesn't correspond to a big-core. + */ +static inline bool dt_has_big_core(struct device_node *dn, + struct thread_groups *tg) +{ + if (parse_thread_groups(dn, tg)) + return false; + + if (tg->property != 1) + return false; + + if (tg->nr_groups < 1) + return false; + + return true; +} + +/* + * get_cpu_thread_group_start : Searches the thread group in tg->thread_list + * that @cpu belongs to. + * + * @cpu : The logical CPU whose thread group is being searched. + * @tg : The thread-group structure of the CPU node which @cpu belongs + * to. + * + * Returns the index to tg->thread_list that points to the the start + * of the thread_group that @cpu belongs to. + * + * Returns -1 if cpu doesn't belong to any of the groups pointed to by + * tg->thread_list. + */ +int get_cpu_thread_group_start(int cpu, struct thread_groups *tg) +{ + int hw_cpu_id = get_hard_smp_processor_id(cpu); + int i, j; + + for (i = 0; i < tg->nr_groups; i++) { + int group_start = i * tg->threads_per_group; + + for (j = 0; j < tg->threads_per_group; j++) { + int idx = group_start + j; + + if (tg->thread_list[idx] == hw_cpu_id) + return group_start; + } + } + + return -1; +} + /** * setup_cpu_maps - initialize the following cpu maps: * cpu_possible_mask @@ -457,6 +605,7 @@ void __init smp_setup_cpu_maps(void) int cpu = 0; int nthreads = 1; + has_big_cores = true; DBG("smp_setup_cpu_maps()\n"); cpu_to_phys_id = __va(memblock_alloc(nr_cpu_ids * sizeof(u32), @@ -467,6 +616,7 @@ void __init smp_setup_cpu_maps(void) const __be32 *intserv; __be32 cpu_be; int j, len; + struct thread_groups tg; DBG(" * %pOF...\n", dn); @@ -505,6 +655,10 @@ void __init smp_setup_cpu_maps(void) cpu++; } + if (has_big_cores && !dt_has_big_core(dn, &tg)) { + has_big_cores = false; + } + if (cpu >= nr_cpu_ids) { of_node_put(dn); break; diff --git a/arch/powerpc/kernel/sysfs.c b/arch/powerpc/kernel/sysfs.c index 755dc98..f5717de 100644 --- a/arch/powerpc/kernel/sysfs.c +++ b/arch/powerpc/kernel/sysfs.c @@ -18,6 +18,7 @@ #include <asm/smp.h> #include <asm/pmc.h> #include <asm/firmware.h> +#include <asm/cputhreads.h> #include "cacheinfo.h" #include "setup.h" @@ -1025,6 +1026,33 @@ static ssize_t show_physical_id(struct device *dev, } static DEVICE_ATTR(physical_id, 0444, show_physical_id, NULL); +static ssize_t show_small_core_siblings(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct cpu *cpu = container_of(dev, struct cpu, dev); + struct device_node *dn = of_get_cpu_node(cpu->dev.id, NULL); + struct thread_groups tg; + int i, j; + ssize_t ret = 0; + + if (parse_thread_groups(dn, &tg)) + return -ENODATA; + + i = get_cpu_thread_group_start(cpu->dev.id, &tg); + + if (i == -1) + return -ENODATA; + + for (j = 0; j < tg.threads_per_group - 1; j++) + ret += sprintf(buf + ret, "%d,", tg.thread_list[i + j]); + + ret += sprintf(buf + ret, "%d\n", tg.thread_list[i + j]); + + return ret; +} +static DEVICE_ATTR(small_core_siblings, 0444, show_small_core_siblings, NULL); + static int __init topology_init(void) { int cpu, r; @@ -1048,6 +1076,13 @@ static int __init topology_init(void) register_cpu(c, cpu); device_create_file(&c->dev, &dev_attr_physical_id); + + if (has_big_cores) { + const struct device_attribute *attr = + &dev_attr_small_core_siblings; + + device_create_file(&c->dev, attr); + } } } r = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "powerpc/topology:online",