Messages in this thread Patch in this message | | | From | Vincent Guittot <> | Date | Tue, 11 Mar 2014 14:18:53 +0100 | Subject | Re: [RFC 4/6] sched: powerpc: create a dedicated topology table |
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On 11 March 2014 11:08, Preeti U Murthy <preeti@linux.vnet.ibm.com> wrote: > 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, }, > +};
Not exactly like that but something like below
+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) }, +#endif + { cpu_cpu_mask, SD_INIT_NAME(DIE) }, + { NULL, }, +}; + +static void __init set_sched_topology(void) +{ +#ifdef CONFIG_SCHED_SMT + powerpc_topology[0].sd_flags |= arch_sd_sibling_asym_packing(); +#endif + sched_domain_topology = powerpc_topology; +}
> > 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; >> >
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