Messages in this thread Patch in this message | | | From | Vaidyanathan Srinivasan <> | Subject | [RFC PATCH v1 3/5] Collect statistics required for powersave balance | Date | Wed, 24 Sep 2008 21:48:09 +0530 |
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Update sched domain level statistics with the minimum load and group leader who can pull more tasks. Also suggest a powersave movement if the domain is otherwise balanced.
Signed-off-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> ---
kernel/sched.c | 97 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 97 insertions(+), 0 deletions(-)
diff --git a/kernel/sched.c b/kernel/sched.c index 8c394a4..dd87061 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -3219,6 +3219,103 @@ void update_sd_loads(struct sd_loads *sdl, struct group_loads *gl) } +#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) +void update_powersavings_group_loads(struct sd_loads *sdl, + struct group_loads *gl, + enum cpu_idle_type idle) +{ + int group_capacity = gl->group->__cpu_power / SCHED_LOAD_SCALE; + + /* + * Busy processors will not participate in power savings + * balance. + */ + if (idle == CPU_NOT_IDLE || + !(sdl->sd->flags & SD_POWERSAVINGS_BALANCE)) + return; + + /* + * If the local group is idle or completely loaded + * no need to do power savings balance at this domain + * Same case of non-local groups as well + */ + if (gl->nr_running >= group_capacity || gl->nr_running == 0) + return; + + /* + * Calculate the group which has the least non-idle load. + * This is the group from where we need to pick up the load + * for saving power + */ + if (!sdl->min_load_group.group) + sdl->min_load_group = *gl; + else { + if (gl->nr_running < sdl->min_load_group.nr_running) + sdl->min_load_group = *gl; + /* If the loads are equal, then prefer the cpu with + * less logical number + */ + else if (gl->nr_running == sdl->min_load_group.nr_running && + first_cpu(gl->group->cpumask) < + first_cpu(sdl->min_load_group.group->cpumask)) + sdl->min_load_group = *gl; + } + + /* + * Calculate the group which is almost near its + * capacity but still has some space to pick up some load + * from other group and save more power + */ + + if (gl->nr_running > 0 && gl->nr_running <= group_capacity - 1) { + if (!sdl->power_save_leader_group.group) + sdl->power_save_leader_group = *gl; + else { + if (gl->nr_running > + sdl->power_save_leader_group.nr_running) + sdl->power_save_leader_group = *gl; + else if (gl->nr_running == + sdl->power_save_leader_group.nr_running && + first_cpu(gl->group->cpumask) < + first_cpu(sdl->min_load_group.group->cpumask)) + sdl->power_save_leader_group = *gl; + } + } +} + +static struct sched_group *powersavings_balance_group(struct sd_loads *sdl, + struct group_loads *gl, enum cpu_idle_type idle, + unsigned long *imbalance) +{ + *imbalance = 0; + if (idle == CPU_NOT_IDLE || !(sdl->sd->flags & SD_POWERSAVINGS_BALANCE)) + return NULL; + + if (sdl->local.group == sdl->power_save_leader_group.group && + sdl->power_save_leader_group.group != + sdl->min_load_group.group) { + *imbalance = sdl->min_load_group.avg_load_per_task; + return sdl->min_load_group.group; + } + + return NULL; +} +#else +void update_powersavings_group_loads(struct sd_loads *sdl, + struct group_loads *gl, enum cpu_idle_type idle) +{ + return; +} + +static struct sched_group *powersavings_balance_group(struct sd_loads *sdl, + struct group_loads *gl, enum cpu_idle_type idle, + unsigned long *imbalance) +{ + *imbalance = 0; + return NULL; +} +#endif + /* * find_busiest_group finds and returns the busiest CPU group within the * domain. It calculates and returns the amount of weighted load which
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