lkml.org 
[lkml]   [2014]   [May]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[RFC PATCH 03/16] sched: Introduce sd energy data structures
    Date
    From: Dietmar Eggemann <dietmar.eggemann@arm.com>

    The struct sched_energy represents the per scheduler group related data
    which is needed for the energy aware scheduler.

    It contains a pointer to a struct capacity_state array which contains
    (compute capacity, power consumption @ this compute capacity) tuples.

    The struct sched_group_energy wraps struct sched_energy and an atomic
    reference counter, latter is used for scheduler internal bookkeeping of
    data allocation and freeing.

    Allocation and freeing of struct sched_group_energy uses the existing
    infrastructure of the scheduler which is currently used for the other sd
    hierarchy data structures (e.g. struct sched_domain). That's why struct
    sd_data is provisioned with a per cpu struct sched_group_energy double
    pointer.

    The struct sched_group gets a pointer to a struct sched_group_energy.

    The function ptr sched_domain_energy_f is introduced into struct
    sched_domain_topology_level which will allow the arch to set a pass a
    particular struct sd_energy from the topology shim layer into the
    scheduler core.

    The function ptr sched_domain_energy_f has an 'int cpu' parameter since
    the folding of two adjacent sd levels via sd degenerate doesn't work
    for all sd levels. E.g. it is not possible to use this feature to
    provide per-cpu sd energy in sd level DIE (former CPU) on ARM's TC2
    platform.

    It was discussed that the folding of sd levels approach is preferable
    over the cpu parameter approach, simply because the user (the arch
    specifying the sd topology table) can introduce less errors. But since
    it is not working, the 'int cpu' parameter is the only way out. It's
    possible to use the folding of sd levels approach for
    sched_domain_flags_f and the cpu parameter approach for the
    sched_domain_energy_f at the same time set-up though. With the use of
    the 'int cpu' parameter, an extra check function has to be provided to
    make sure that all cpus spanned by a scheduler building block (e.g a
    sched domain or a group) are provisioned with the same energy data.

    Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
    ---
    include/linux/sched.h | 24 ++++++++++++++++++++++++
    kernel/sched/sched.h | 10 ++++++++++
    2 files changed, 34 insertions(+)

    diff --git a/include/linux/sched.h b/include/linux/sched.h
    index 261a419..4eb149b 100644
    --- a/include/linux/sched.h
    +++ b/include/linux/sched.h
    @@ -909,6 +909,21 @@ struct sched_domain_attr {

    extern int sched_domain_level_max;

    +#ifdef CONFIG_SCHED_ENERGY
    +struct capacity_state {
    + int cap; /* compute capacity */
    + int power; /* power consumption at this compute capacity */
    +};
    +
    +struct sched_energy {
    + long max_capacity; /* maximal compute capacity */
    + int idle_power; /* power consumption in idle state */
    + int wakeup_energy; /* energy for wakeup->sleep cycle (x1024) */
    + int nr_cap_states; /* number of capacity states */
    + struct capacity_state *cap_states; /* ptr to capacity state array */
    +};
    +#endif
    +
    struct sched_group;

    struct sched_domain {
    @@ -1007,6 +1022,9 @@ bool cpus_share_cache(int this_cpu, int that_cpu);

    typedef const struct cpumask *(*sched_domain_mask_f)(int cpu);
    typedef const int (*sched_domain_flags_f)(void);
    +#ifdef CONFIG_SCHED_ENERGY
    +typedef const struct sched_energy *(*sched_domain_energy_f)(int cpu);
    +#endif

    #define SDTL_OVERLAP 0x01

    @@ -1014,11 +1032,17 @@ struct sd_data {
    struct sched_domain **__percpu sd;
    struct sched_group **__percpu sg;
    struct sched_group_power **__percpu sgp;
    +#ifdef CONFIG_SCHED_ENERGY
    + struct sched_group_energy **__percpu sge;
    +#endif
    };

    struct sched_domain_topology_level {
    sched_domain_mask_f mask;
    sched_domain_flags_f sd_flags;
    +#ifdef CONFIG_SCHED_ENERGY
    + sched_domain_energy_f energy;
    +#endif
    int flags;
    int numa_level;
    struct sd_data data;
    diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
    index 456e492..c566f5e 100644
    --- a/kernel/sched/sched.h
    +++ b/kernel/sched/sched.h
    @@ -755,12 +755,22 @@ struct sched_group_power {
    unsigned long cpumask[0]; /* iteration mask */
    };

    +#ifdef CONFIG_SCHED_ENERGY
    +struct sched_group_energy {
    + atomic_t ref;
    + struct sched_energy data;
    +};
    +#endif
    +
    struct sched_group {
    struct sched_group *next; /* Must be a circular list */
    atomic_t ref;

    unsigned int group_weight;
    struct sched_group_power *sgp;
    +#ifdef CONFIG_SCHED_ENERGY
    + struct sched_group_energy *sge;
    +#endif

    /*
    * The CPUs this group covers.
    --
    1.7.9.5



    \
     
     \ /
      Last update: 2014-05-23 21:01    [W:4.076 / U:0.040 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site