Messages in this thread Patch in this message | | | Subject | sched: Improve load balancing in the presence of idle CPUs | From | Jason Low <> | Date | Mon, 30 Mar 2015 11:55:29 -0700 |
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Hi Preeti,
I noticed that another commit 4a725627f21d converted the check in nohz_kick_needed() from idle_cpu() to rq->idle_balance, causing a potentially outdated value to be used if this cpu is able to pull tasks using rebalance_domains(), and nohz_kick_needed() directly returning false.
Would this patch also help address some of the issue you are seeing?
Signed-off-by: Jason Low <jason.low2@hp.com> --- kernel/sched/fair.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index fdae26e..ba8ec1a 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -7644,7 +7644,7 @@ static void nohz_idle_balance(struct rq *this_rq, enum cpu_idle_type idle) * balancing owner will pick it up. */ if (need_resched()) - break; + goto end; rq = cpu_rq(balance_cpu); @@ -7687,7 +7687,7 @@ static inline bool nohz_kick_needed(struct rq *rq) int nr_busy, cpu = rq->cpu; bool kick = false; - if (unlikely(rq->idle_balance)) + if (unlikely(idle_cpu(cpu))) return false; /* -- 1.7.2.5
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