tip-bot for Peter Zijlstra <tip...@zytor.com> wrote:
> Commit-ID: 863bffc80898b8df295ebac111af2335ec05f85d
> Gitweb: http://git.kernel.org/tip/863bffc80898b8df295ebac111af2335ec05f85d
> Author: Peter Zijlstra <pet...@infradead.org>
> AuthorDate: Wed, 28 Aug 2013 11:44:39 +0200
> Committer: Ingo Molnar <mi...@kernel.org>
> CommitDate: Thu, 12 Sep 2013 19:14:43 +0200
>
> sched/fair: Fix group power_orig computation
>
> When looking at the code I noticed we don't actually compute
> sgp->power_orig correctly for groups, fix that.
>
> Currently the only consumer of that value is fix_small_capacity()
> which is only used on POWER7+ and that code excludes this case by
> being limited to SD_SHARE_CPUPOWER which is only ever set on the SMT
> domain which must be the lowest domain and this has singleton groups.
>
> So nothing should be affected by this change.
>
> Cc: Michael Neuling <mi...@neuling.org>
> Signed-off-by: Peter Zijlstra <pet...@infradead.org>
> Link: http://lkml.kernel.org/n/tip-db2pe0vxwunv37plc7onn...@git.kernel.org
> Signed-off-by: Ingo Molnar <mi...@kernel.org>
FWIW, this doesn't seem to break POWER7.
Thanks!
Mikey
> ---
> kernel/sched/fair.c | 16 +++++++++++-----
> 1 file changed, 11 insertions(+), 5 deletions(-)
>
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index f9f4385..baba313 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -4450,7 +4450,7 @@ void update_group_power(struct sched_domain *sd, int
> cpu)
> {
> struct sched_domain *child = sd->child;
> struct sched_group *group, *sdg = sd->groups;
> - unsigned long power;
> + unsigned long power, power_orig;
> unsigned long interval;
>
> interval = msecs_to_jiffies(sd->balance_interval);
> @@ -4462,7 +4462,7 @@ void update_group_power(struct sched_domain *sd, int
> cpu)
> return;
> }
>
> - power = 0;
> + power_orig = power = 0;
>
> if (child->flags & SD_OVERLAP) {
> /*
> @@ -4470,8 +4470,12 @@ void update_group_power(struct sched_domain *sd, int
> cpu)
> * span the current group.
> */
>
> - for_each_cpu(cpu, sched_group_cpus(sdg))
> - power += power_of(cpu);
> + for_each_cpu(cpu, sched_group_cpus(sdg)) {
> + struct sched_group *sg = cpu_rq(cpu)->sd->groups;
> +
> + power_orig += sg->sgp->power_orig;
> + power += sg->sgp->power;
> + }
> } else {
> /*
> * !SD_OVERLAP domains can assume that child groups
> @@ -4480,12 +4484,14 @@ void update_group_power(struct sched_domain *sd, int
> cpu)
>
> group = child->groups;
> do {
> + power_orig += group->sgp->power_orig;
> power += group->sgp->power;
> group = group->next;
> } while (group != child->groups);
> }
>
> - sdg->sgp->power_orig = sdg->sgp->power = power;
> + sdg->sgp->power_orig = power_orig;
> + sdg->sgp->power = power;
> }
>
> /*
>
--
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