Re: [request for stable inclusion] nohz: Fix another inconsistency between CONFIG_NO_HZ=n and nohz=off

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On Tue, Jun 24, 2014 at 12:02:34PM +0800, Rui Xiang wrote:
> Hi Greg or Thomas,
> 
> 0e576acbc1d9600cf2d9b4a141a2554639959d50 
> nohz: Fix another inconsistency between CONFIG_NO_HZ=n and nohz=off
> 
> This fixed an inconsistency about nohz. 
> 
> Without this patch, When we boot with nohz=off and CONFIG_NO_HZ=Y, 
> and the system is idle, powertop shows the cpu is always in polling
> state. It can affect the performance in some cases. 
> 
> *without patch*
>      PowerTOP version 1.13      (C) 2007 Intel Corporation
> 
> Cn                Avg residency       P-states (frequencies)
> C0 (cpu running)        ( 0.0%)       Turbo Mode     0.0%
> polling          70.3ms (100.3%)        2.40 Ghz     0.0%
> C1 mwait          0.0ms ( 0.0%)         2.27 Ghz     0.0%
> C2 mwait          0.0ms ( 0.0%)         2.14 Ghz     0.0%
> C3 mwait          0.0ms ( 0.0%)         1.60 Ghz   100.0%
> 
> *with patch*
>      PowerTOP version 1.13      (C) 2007 Intel Corporation
> 
> Cn                Avg residency       P-states (frequencies)
> C0 (cpu running)        ( 0.3%)       Turbo Mode     0.0%
> polling           0.0ms ( 0.0%)         2.40 Ghz     0.0%
> C1 mwait          0.0ms ( 0.0%)         2.27 Ghz     0.0%
> C2 mwait          0.0ms ( 0.0%)         2.14 Ghz     0.0%
> C3 mwait          3.9ms (99.7%)         1.60 Ghz   100.0%
> 
> 
> This patch looks applicable to stable-3.4 and stable 3.10. It can be
> applyed to 3.10 cleanly, but should be added some adjustment for 3.4.
> 
> And what do you think?

Looks good to me, I've queued this up, thanks.

greg k-h
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