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The affinity between ARM processors is defined in the MPIDR register. We can identify which processors are in the same cluster, and which ones have performance interdependency. We can define the cpu topology of ARM platform, that is then used by sched_mc and sched_smt. The default state of sched_mc and sched_smt config is disable. When enabled, the behavior of the scheduler can be modified with sched_mc_power_savings and sched_smt_power_savings sysfs interfaces. Changes since v4 : * Remove unnecessary parentheses and blank lines Changes since v3 : * Update the format of printk message * Remove blank line Changes since v2 : * Update the commit message and some comments Changes since v1 : * Update the commit message * Add read_cpuid_mpidr in arch/arm/include/asm/cputype.h * Modify header of arch/arm/kernel/topology.c * Modify tests and manipulation of MPIDR's bitfields * Modify the place and dependancy of the config * Modify Noop functions Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Reviewed-by: Amit Kucheria <amit.kucheria@linaro.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
40 lines
1,005 B
C
40 lines
1,005 B
C
#ifndef _ASM_ARM_TOPOLOGY_H
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#define _ASM_ARM_TOPOLOGY_H
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#ifdef CONFIG_ARM_CPU_TOPOLOGY
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#include <linux/cpumask.h>
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struct cputopo_arm {
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int thread_id;
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int core_id;
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int socket_id;
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cpumask_t thread_sibling;
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cpumask_t core_sibling;
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};
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extern struct cputopo_arm cpu_topology[NR_CPUS];
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#define topology_physical_package_id(cpu) (cpu_topology[cpu].socket_id)
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#define topology_core_id(cpu) (cpu_topology[cpu].core_id)
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#define topology_core_cpumask(cpu) (&cpu_topology[cpu].core_sibling)
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#define topology_thread_cpumask(cpu) (&cpu_topology[cpu].thread_sibling)
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#define mc_capable() (cpu_topology[0].socket_id != -1)
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#define smt_capable() (cpu_topology[0].thread_id != -1)
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void init_cpu_topology(void);
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void store_cpu_topology(unsigned int cpuid);
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const struct cpumask *cpu_coregroup_mask(unsigned int cpu);
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#else
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static inline void init_cpu_topology(void) { }
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static inline void store_cpu_topology(unsigned int cpuid) { }
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#endif
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#include <asm-generic/topology.h>
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#endif /* _ASM_ARM_TOPOLOGY_H */
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