Modify the CPU topology policy according to the sched_mc level and the cortex family

Signed-off-by: Vincent Guittot vincent.guittot@linaro.org --- arch/arm/kernel/topology.c | 104 +++++++++++++++++++++++++++++++++++-------- 1 files changed, 84 insertions(+), 20 deletions(-)

diff --git a/arch/arm/kernel/topology.c b/arch/arm/kernel/topology.c index d89c66c..34512fe 100644 --- a/arch/arm/kernel/topology.c +++ b/arch/arm/kernel/topology.c @@ -44,6 +44,13 @@ struct cputopo_arm cpu_topology[NR_CPUS];

/* + * cpu topology mask management + */ + +static void default_cpu_topology_mask(void); +static void (*set_cpu_topology_mask)(void) = default_cpu_topology_mask; + +/* * default topology function */

@@ -66,26 +73,33 @@ static void clear_cpu_topology_mask(void) smp_wmb(); }

-static void default_cpu_topology_mask(unsigned int cpuid) +/* + * default_cpu_topology_mask set the core and thread mask as described in the + * ARM ARM + */ +static void default_cpu_topology_mask(void) { - struct cputopo_arm *cpuid_topo = &cpu_topology[cpuid]; - unsigned int cpu; + unsigned int cpuid, cpu;

- for_each_possible_cpu(cpu) { - struct cputopo_arm *cpu_topo = &cpu_topology[cpu]; + for_each_possible_cpu(cpuid) { + struct cputopo_arm *cpuid_topo = &cpu_topology[cpuid];

- if (cpuid_topo->socket_id == cpu_topo->socket_id) { - cpumask_set_cpu(cpuid, &cpu_topo->core_sibling); - if (cpu != cpuid) - cpumask_set_cpu(cpu, - &cpuid_topo->core_sibling); + for_each_possible_cpu(cpu) { + struct cputopo_arm *cpu_topo = &cpu_topology[cpu];

- if (cpuid_topo->core_id == cpu_topo->core_id) { - cpumask_set_cpu(cpuid, - &cpu_topo->thread_sibling); + if (cpuid_topo->socket_id == cpu_topo->socket_id) { + cpumask_set_cpu(cpuid, &cpu_topo->core_sibling); if (cpu != cpuid) cpumask_set_cpu(cpu, - &cpuid_topo->thread_sibling); + &cpuid_topo->core_sibling); + + if (cpuid_topo->core_id == cpu_topo->core_id) { + cpumask_set_cpu(cpuid, + &cpu_topo->thread_sibling); + if (cpu != cpuid) + cpumask_set_cpu(cpu, + &cpuid_topo->thread_sibling); + } } } } @@ -93,6 +107,55 @@ static void default_cpu_topology_mask(unsigned int cpuid) }

/* + * For Cortex-A9 MPcore dual core, we emulate a multi-package single core + * topology in power mode. + */ +static void power_cpu_topology_mask_CA9(void) +{ + unsigned int cpuid; + for_each_possible_cpu(cpuid) { + struct cputopo_arm *cpuid_topo = &(cpu_topology[cpuid]); + + cpumask_set_cpu(cpuid, &cpuid_topo->core_sibling); + cpumask_set_cpu(cpuid, &cpuid_topo->thread_sibling); + + } + smp_wmb(); +} + +#define ARM_FAMILY_MASK 0xFF0FFFF0 +#define ARM_CORTEX_A9_FAMILY 0x410FC090 + +/* update_cpu_topology_policy select a cpu topology policy according to the + * available cores. + * TODO: The current version assumes that all cores are exactly the same which + * might not be true. We need to update it to take into account various + * configuration among which system with different kind of core. + */ +static int update_cpu_topology_policy(void) +{ + unsigned long cpuid; + + if (sched_mc_power_savings == POWERSAVINGS_BALANCE_NONE) { + set_cpu_topology_mask = default_cpu_topology_mask; + return 0; + } + + cpuid = read_cpuid_id(); + cpuid &= ARM_FAMILY_MASK; + + switch (cpuid) { + case ARM_CORTEX_A9_FAMILY: + set_cpu_topology_mask = power_cpu_topology_mask_CA9; + break; + default: + set_cpu_topology_mask = default_cpu_topology_mask; + break; + } + + return 0; +} +/* * store_cpu_topology is called at boot when only one cpu is running * and with the mutex cpu_hotplug.lock locked, when several cpus have booted, * which prevents simultaneous write access to cpu_topology array @@ -159,14 +222,15 @@ void store_cpu_topology(unsigned int cpuid) */ int arch_update_cpu_topology(void) { - unsigned int cpuid; - /* clear core mask */ + + /* clear core threads mask */ clear_cpu_topology_mask();

- /* update core and thread sibling masks */ - for_each_possible_cpu(cpuid) { - default_cpu_topology_mask(cpuid); - } + /* set topology policy */ + update_cpu_topology_policy(); + + /* set topology mask and power */ + (*set_cpu_topology_mask)();

return 1; }