Messages in this thread | | | Date | Mon, 13 Feb 2012 13:27:29 +0800 | From | Yong Zhang <> | Subject | Re: [RFC] Extend mwait idle to optimize away IPIs when possible |
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On Thu, Feb 09, 2012 at 06:17:06PM -0800, Venki Pallipadi wrote: > > This should likely work. But, if you do want to use similar logic in > smp_call_function() or idle load balance kick etc, you need additional > bit other than need_resched() as there we only need irq+softirq and > not necessarily a resched.
Yeah, putting resched_idle_cpu() into smp_call_function_*() is a bit ugly though resched could work in the scenario because you have generic_smp_call_function_single_interrupt() called in cpu_idle();
> At this time I am not sure how poll wakeup logic works in MIPS. But,
A typical example is busy loop: void __noreturn cpu_idle(void) { ...
while (1) { tick_nohz_idle_enter(); rcu_idle_enter(); while (!need_resched() && cpu_online(cpu)) { ; } rcu_idle_exit(); tick_nohz_idle_exit(); preempt_enable_no_resched(); schedule(); preempt_disable(); }
... }
> if it is something that is similar to x86 mwait and we can wakeup with > a bit other than TIF_NEED_RESCHED, we can generalize most of the > changes in my RFC and share it across archs.
Yeah, there are many things we could share IMHO, especially the hook in cpu_idle().
Thanks, Yong
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