Messages in this thread | | | Date | Thu, 25 Sep 2008 17:54:20 +0530 | From | Gautham R Shenoy <> | Subject | Re: [RFC PATCH v1 3/5] Collect statistics required for powersave balance |
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On Wed, Sep 24, 2008 at 09:48:09PM +0530, Vaidyanathan Srinivasan wrote: > 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 > + */ Are there groups other than local and non-local ? If not, this comment can be condensed so that it can be applied to all groups :-)
> + 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
-- Thanks and Regards gautham
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