Messages in this thread Patch in this message | | | Date | Tue, 11 Mar 2014 15:38:07 +0530 | From | Preeti U Murthy <> | Subject | Re: [RFC 4/6] sched: powerpc: create a dedicated topology table |
| |
Hi Vincent,
On 03/05/2014 12:48 PM, Vincent Guittot wrote: > 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.
Is the below what you mean as the other solution? If it is so, I would strongly recommend this approach rather than adding another level to the topology level to represent the asymmetric behaviour.
+static struct sched_domain_topology_level powerpc_topology[] = { +#ifdef CONFIG_SCHED_SMT + { cpu_smt_mask, SD_SHARE_CPUPOWER | SD_SHARE_PKG_RESOURCES, SD_INIT_NAME(SMT) | arch_sd_sibling_asym_packing() }, +#endif + { cpu_cpu_mask, SD_INIT_NAME(DIE) }, + { NULL, }, +};
Regards Preeti U Murthy > > 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; >
| |