Create a dedicated topology table for handling asymetric feature. The current proposal creates a new level which describes which groups of CPUs take adavantge of SD_ASYM_PACKING. The useless level will be removed during the build of the sched_domain topology.
Another solution would be to set SD_ASYM_PACKING in the sd_flags of SMT level during the boot sequence and before the build of the sched_domain topology.
Signed-off-by: Vincent Guittot vincent.guittot@linaro.org --- arch/powerpc/kernel/smp.c | 35 +++++++++++++++++++++++++++-------- kernel/sched/core.c | 6 ------ 2 files changed, 27 insertions(+), 14 deletions(-)
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c index ac2621a..75da054 100644 --- a/arch/powerpc/kernel/smp.c +++ b/arch/powerpc/kernel/smp.c @@ -755,6 +755,32 @@ int setup_profiling_timer(unsigned int multiplier) return 0; }
+#ifdef CONFIG_SCHED_SMT +/* cpumask of CPUs with asymetric SMT dependancy */ +static const struct cpumask *cpu_asmt_mask(int cpu) +{ + if (cpu_has_feature(CPU_FTR_ASYM_SMT)) { + printk_once(KERN_INFO "Enabling Asymmetric SMT scheduling\n"); + return topology_thread_cpumask(cpu); + } + return cpumask_of(cpu); +} +#endif + +static struct sched_domain_topology_level powerpc_topology[] = { +#ifdef CONFIG_SCHED_SMT + { cpu_asmt_mask, SD_SHARE_CPUPOWER | SD_SHARE_PKG_RESOURCES | SD_ASYM_PACKING, SD_INIT_NAME(ASMT) }, + { cpu_smt_mask, SD_SHARE_CPUPOWER | SD_SHARE_PKG_RESOURCES, SD_INIT_NAME(SMT) }, +#endif + { cpu_cpu_mask, SD_INIT_NAME(DIE) }, + { NULL, }, +}; + +static void __init set_sched_topology(void) +{ + sched_domain_topology = powerpc_topology; +} + void __init smp_cpus_done(unsigned int max_cpus) { cpumask_var_t old_mask; @@ -779,15 +805,8 @@ void __init smp_cpus_done(unsigned int max_cpus)
dump_numa_cpu_topology();
-} + set_sched_topology();
-int arch_sd_sibling_asym_packing(void) -{ - if (cpu_has_feature(CPU_FTR_ASYM_SMT)) { - printk_once(KERN_INFO "Enabling Asymmetric SMT scheduling\n"); - return SD_ASYM_PACKING; - } - return 0; }
#ifdef CONFIG_HOTPLUG_CPU diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 3479467..7606de0 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -5818,11 +5818,6 @@ static void init_sched_groups_power(int cpu, struct sched_domain *sd) atomic_set(&sg->sgp->nr_busy_cpus, sg->group_weight); }
-int __weak arch_sd_sibling_asym_packing(void) -{ - return 0*SD_ASYM_PACKING; -} - /* * Initializers for schedule domains * Non-inlined to reduce accumulated stack pressure in build_sched_domains() @@ -6000,7 +5995,6 @@ sd_init(struct sched_domain_topology_level *tl, int cpu) if (sd->flags & SD_SHARE_CPUPOWER) { sd->imbalance_pct = 110; sd->smt_gain = 1178; /* ~15% */ - sd->flags |= arch_sd_sibling_asym_packing();
} else if (sd->flags & SD_SHARE_PKG_RESOURCES) { sd->imbalance_pct = 117;