On 08/11/2014 07:03 PM, Peter Zijlstra wrote:
>
> Now I think I see why this is; we've reduced load balancing frequency
> significantly on this machine due to:
We have also changed the value of busy_factor to 32 from 64 across all
domains. This would contribute to increased frequency of load balancing?
Regards
Preeti U Murthy
>
>
> -#define SD_SIBLING_INIT (struct sched_domain) {
> \
> - .min_interval = 1, \
> - .max_interval = 2, \
>
>
> -#define SD_MC_INIT (struct sched_domain) { \
> - .min_interval = 1, \
> - .max_interval = 4, \
>
>
> -#define SD_CPU_INIT (struct sched_domain) { \
> - .min_interval = 1, \
> - .max_interval = 4, \
>
>
> *sd = (struct sched_domain){
> .min_interval = sd_weight,
> .max_interval = 2*sd_weight,
>
> Which both increased the min and max value significantly for all domains
> involved.
>
> That said; I think we might want to do something like the below; I can
> imagine decreasing load balancing too much will negatively impact other
> workloads.
>
> Maybe slightly modified to make sure the first domain has a min_interval
> of 1.
>
> ---
> kernel/sched/core.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index 1211575a2208..67ed5d854da1 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -6049,8 +6049,8 @@ sd_init(struct sched_domain_topology_level *tl, int cpu)
> sd_flags &= ~TOPOLOGY_SD_FLAGS;
>
> *sd = (struct sched_domain){
> - .min_interval = sd_weight,
> - .max_interval = 2*sd_weight,
> + .min_interval = max(1, sd_weight/2),
> + .max_interval = sd_weight,
> .busy_factor = 32,
> .imbalance_pct = 125,
>
> @@ -6076,7 +6076,7 @@ sd_init(struct sched_domain_topology_level *tl, int cpu)
> ,
>
> .last_balance = jiffies,
> - .balance_interval = sd_weight,
> + .balance_interval = max(1, sd_weight/2),
> .smt_gain = 0,
> .max_newidle_lb_cost = 0,
> .next_decay_max_lb_cost = jiffies,
>
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
