Messages in this thread | | | Date | Fri, 24 Oct 2008 14:05:44 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH 1/1] SGI X86 UV: Provide a System Activity Indicator driver |
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* Pavel Machek <pavel@suse.cz> wrote:
> On Fri 2008-10-24 04:19:04, Mike Travis wrote: > > [Ingo - could you let me know what's holding up this driver? > > Thanks!, Mike] > > I thought that... > > > +static __init void uv_scir_register_cpu_notifier(void) > > +{ > > + hotcpu_notifier(uv_scir_cpu_notify, 0); > > + idle_notifier_register(&uv_idle_notifier); > > +} > > ...Ingo said that idle_notifier_register is deprecated and going away?
yes, but i suspect Mike noticed that i acked Len's use of idle notifiers in the ACPI tree, and now he wants to refresh this discussion?
i cannot really believe why anyone would want to slow down the from-idle hotpath in such a lame way:
+ } else if (action == IDLE_END) { + + uv_hub_info->scir.state |= SCIR_CPU_ACTIVITY; + uv_hub_info->scir.idle_off += elapsed; + uv_hub_info->scir.last = jiffies; + }
with such a lame and low-res timestamp:
+ unsigned long elapsed = jiffies - uv_hub_info->scir.last;
it's an absolutely pointless act of adding overhead. Just use a regular timer mechanism to update uv_hub_info->scir.idle_off.
Ingo
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