Messages in this thread | | | Subject | Re: [RFC] sched: Ensure cpu_power periodic update | From | Peter Zijlstra <> | Date | Thu, 15 Dec 2011 11:08:30 +0100 |
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On Mon, 2011-12-12 at 20:21 +0100, Vincent Guittot wrote: > With a lot of small tasks, the softirq sched is nearly never called > when no_hz is enable. In this case the load_balance is mainly called with > the newly_idle mode which doesn't update the cpu_power. > Add a next_update field which ensure a maximum update period when > there is short activity
> + if (local_group) { > + if (idle != CPU_NEWLY_IDLE) { > + if (balance_cpu != this_cpu) { > + *balance = 0; > + return; > + } > + update_group_power(sd, this_cpu); > + } else if (time_after_eq(jiffies, group->sgp->next_update)) > + update_group_power(sd, this_cpu); > }
Hmm, I would have expected it to be called from the NOHZ balancing path instead of the new_idle path. Your changelog fails to mentions any considerations on this..
Then again, its probably easier to keep update_group_power on this_cpu than to allow a remote update of your cpu_power.
So I'm not opposed to this patch, I'd just like a little extra clarification.
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