On 24 October 2012 17:21, Santosh Shilimkar <santosh.shilim...@ti.com> wrote:
> On Sunday 07 October 2012 01:13 PM, Vincent Guittot wrote:
>>
>> Look for an idle CPU close the pack buddy CPU whenever possible.
>
> s/close/close to
yes
>
>> The goal is to prevent the wake up of a CPU which doesn't share the power
>> line of the pack CPU
>>
>> Signed-off-by: Vincent Guittot <vincent.guit...@linaro.org>
>> ---
>> kernel/sched/fair.c | 18 ++++++++++++++++++
>> 1 file changed, 18 insertions(+)
>>
>> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
>> index 6df53b5..f76acdc 100644
>> --- a/kernel/sched/fair.c
>> +++ b/kernel/sched/fair.c
>> @@ -5158,7 +5158,25 @@ static struct {
>>
>> static inline int find_new_ilb(int call_cpu)
>> {
>> + struct sched_domain *sd;
>> int ilb = cpumask_first(nohz.idle_cpus_mask);
>> + int buddy = per_cpu(sd_pack_buddy, call_cpu);
>> +
>> + /*
>> + * If we have a pack buddy CPU, we try to run load balance on a
>> CPU
>> + * that is close to the buddy.
>> + */
>> + if (buddy != -1)
>> + for_each_domain(buddy, sd) {
>> + if (sd->flags & SD_SHARE_CPUPOWER)
>> + continue;
>
> Do you mean SD_SHARE_POWERLINE here ?
No, I just don't want to take hyperthread level for ILB
>
>> +
>> + ilb = cpumask_first_and(sched_domain_span(sd),
>> + nohz.idle_cpus_mask);
>> +
>> + if (ilb < nr_cpu_ids)
>> + break;
>> + }
>>
>> if (ilb < nr_cpu_ids && idle_cpu(ilb))
>> return ilb;
>>
> Can you please expand "idle CPU _close_ the pack buddy CPU" ?
The goal is to packed the tasks on the pack buddy CPU so when the
scheduler needs to start ILB, I try to wake up a CPU that is close to
the buddy and preferably in the same cluster
>
> Regards
> santosh
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