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    Subject[RFC PATCH v3 2/5] sched: favour lower logical cpu number for sched_mc balance
    Date
    Just in case two groups have identical load, prefer to move load to lower
    logical cpu number rather than the present logic of moving to higher logical
    number.

    find_busiest_group() tries to look for a group_leader that has spare capacity
    to take more tasks and freeup an appropriate least loaded group. Just in case
    there is a tie and the load is equal, then the group with higher logical number
    is favoured. This conflicts with user space irqbalance daemon that will move
    interrupts to lower logical number if the system utilisation is very low.

    Signed-off-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
    ---

    kernel/sched.c | 4 ++--
    1 files changed, 2 insertions(+), 2 deletions(-)

    diff --git a/kernel/sched.c b/kernel/sched.c
    index 0dd6cf6..d910496 100644
    --- a/kernel/sched.c
    +++ b/kernel/sched.c
    @@ -3251,7 +3251,7 @@ find_busiest_group(struct sched_domain *sd, int this_cpu,
    */
    if ((sum_nr_running < min_nr_running) ||
    (sum_nr_running == min_nr_running &&
    - first_cpu(group->cpumask) <
    + first_cpu(group->cpumask) >
    first_cpu(group_min->cpumask))) {
    group_min = group;
    min_nr_running = sum_nr_running;
    @@ -3267,7 +3267,7 @@ find_busiest_group(struct sched_domain *sd, int this_cpu,
    if (sum_nr_running <= group_capacity - 1) {
    if (sum_nr_running > leader_nr_running ||
    (sum_nr_running == leader_nr_running &&
    - first_cpu(group->cpumask) >
    + first_cpu(group->cpumask) <
    first_cpu(group_leader->cpumask))) {
    group_leader = group;
    leader_nr_running = sum_nr_running;


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