Re: [Xen-devel] [PATCH RFC v3 3/6] sched/idle: Add a generic poll before enter real idle path

[Peter Zijlstra <peterz@xxxxxxxxxxxxx>]

On Mon, Nov 13, 2017 at 06:06:02PM +0800, Quan Xu wrote:
> From: Yang Zhang <yang.zhang.wz@xxxxxxxxx>
> 
> Implement a generic idle poll which resembles the functionality
> found in arch/. Provide weak arch_cpu_idle_poll function which
> can be overridden by the architecture code if needed.

No, we want less of those magic hooks, not more.

> Interrupts arrive which may not cause a reschedule in idle loops.
> In KVM guest, this costs several VM-exit/VM-entry cycles, VM-entry
> for interrupts and VM-exit immediately. Also this becomes more
> expensive than bare metal. Add a generic idle poll before enter
> real idle path. When a reschedule event is pending, we can bypass
> the real idle path.

Why not do a HV specific idle driver?

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