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* Re: [PATCH] Remove timer frequency choice if tickless is enabled
       [not found] ` <20080112032718.GA3946@Pilar.socal.rr.com>
@ 2008-01-14  8:25   ` Ingo Molnar
  2008-01-14  8:28     ` Peter Zijlstra
  0 siblings, 1 reply; 2+ messages in thread
From: Ingo Molnar @ 2008-01-14  8:25 UTC (permalink / raw)
  To: Carlos R. Mafra; +Cc: linux-kernel, Peter Zijlstra


(lkml Cc:-ed)

* Carlos R. Mafra <crmafra2@gmail.com> wrote:

>  choice
>  	prompt "Timer frequency"
> +	depends on !NO_HZ
>  	default HZ_250
>  	help
>  	 Allows the configuration of the timer frequency. It is customary

we are not there yet to be able to do this. With NO_HZ the tick is only 
disabled when we go idle - but it still runs (and we rely on it, for 
example in the scheduler code) while we are non-idle. Peter Zijlstra is 
working on the 'high-res scheduler tick' feature to remove the scheduler 
dependencies.

	Ingo

^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: [PATCH] Remove timer frequency choice if tickless is enabled
  2008-01-14  8:25   ` [PATCH] Remove timer frequency choice if tickless is enabled Ingo Molnar
@ 2008-01-14  8:28     ` Peter Zijlstra
  0 siblings, 0 replies; 2+ messages in thread
From: Peter Zijlstra @ 2008-01-14  8:28 UTC (permalink / raw)
  To: Ingo Molnar; +Cc: Carlos R. Mafra, linux-kernel


On Mon, 2008-01-14 at 09:25 +0100, Ingo Molnar wrote:
> (lkml Cc:-ed)
> 
> * Carlos R. Mafra <crmafra2@gmail.com> wrote:
> 
> >  choice
> >  	prompt "Timer frequency"
> > +	depends on !NO_HZ
> >  	default HZ_250
> >  	help
> >  	 Allows the configuration of the timer frequency. It is customary
> 
> we are not there yet to be able to do this. With NO_HZ the tick is only 
> disabled when we go idle - but it still runs (and we rely on it, for 
> example in the scheduler code) while we are non-idle. Peter Zijlstra is 
> working on the 'high-res scheduler tick' feature to remove the scheduler 
> dependencies.

Yes, and even then we're still not there, there are various other
features that are tick driven, among them the RCU quiecent state
machine.


^ permalink raw reply	[flat|nested] 2+ messages in thread

end of thread, other threads:[~2008-01-14  8:28 UTC | newest]

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     [not found] <20080112020026.GB5849@Pilar.physics.ucla.edu>
     [not found] ` <20080112032718.GA3946@Pilar.socal.rr.com>
2008-01-14  8:25   ` [PATCH] Remove timer frequency choice if tickless is enabled Ingo Molnar
2008-01-14  8:28     ` Peter Zijlstra

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