Messages in this thread | | | Date | Tue, 09 Apr 2013 18:38:22 +0800 | From | Alex Shi <> | Subject | Re: [patch v3 6/8] sched: consider runnable load average in move_tasks |
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On 04/09/2013 04:58 PM, Vincent Guittot wrote: >>> >> How do you ensure that runnable_avg_period and runnable_avg_sum are >>> >> coherent ? an update of the statistic can occur in the middle of your >>> >> sequence. >> > >> > Thanks for your question, Vincent! >> > the runnable_avg_period and runnable_avg_sum, only updated in >> > __update_entity_runnable_avg(). >> > Yes, I didn't see some locks to ensure the coherent of them. but they >> > are updated closely, and it is not big deal even a little incorrect to >> > their value. These data are collected periodically, don't need very very >> > precise at every time. >> > Am I right? :) > The problem mainly appears during starting phase (the 1st 345ms) when > runnable_avg_period has not reached the max value yet so you can have > avg.runnable_avg_sum greater than avg.runnable_avg_period. In a worst > case, runnable_avg_sum could be twice runnable_avg_period
Oh, That's a serious problem. Do you catch it in real word or in code? Could you explain more for details?
-- Thanks Alex
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