Re: [PATCH] timer: Lazily wakup nohz CPU when adding new timer.

[Viresh Kumar]

On 22-10-15, 14:40, Yunhong Jiang wrote:
> A naive question is, why it's sure a tick will happen when the tickless 
> processor is in idle?

How do you get this impression? I don't think anyone has said that.

We are talking about deferrable timers, which by design are only
required if the target CPU is not-idle. If it is idle, then the timer
isn't required to be serviced until the CPU wakes up. And the CPU can
take whatever time it wants to wake up again.

> Is it because scheduler load balance is sure to send a 
> tick to the processor in future?

No. We aren't expecting the CPU to wake up any time soon. Just ignore
the deferrable timer.

-- 
viresh
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