linux-kernel - Re: [PATCH V3] cpuidle/governors: Fix logic in selection of idle states

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Message-ID: <52F1B773.6050901@linux.vnet.ibm.com>
Date:	Wed, 05 Feb 2014 09:30:51 +0530
From:	Preeti U Murthy <preeti@...ux.vnet.ibm.com>
To:	Arjan van de Ven <arjan@...ux.intel.com>
CC:	linux-pm@...r.kernel.org, rjw@...ysocki.net,
	linux-kernel@...r.kernel.org, len.brown@...el.com,
	benh@...nel.crashing.org, daniel.lezcano@...aro.org,
	srivatsa.bhat@...ux.vnet.ibm.com, paulmck@...ux.vnet.ibm.com,
	svaidy@...ux.vnet.ibm.com
Subject: Re: [PATCH V3] cpuidle/governors: Fix logic in selection of idle
 states

Hi Arjan,

On 02/04/2014 08:22 PM, Arjan van de Ven wrote:
> On 2/4/2014 12:35 AM, Preeti U Murthy wrote:
>> The cpuidle governors today are not handling scenarios where no idle
>> state
>> can be chosen. Such scenarios coud arise if the user has disabled all the
>> idle states at runtime or the latency requirement from the cpus is
>> very strict.
>>
>> The menu governor returns 0th index of the idle state table when no other
>> idle state is suitable. This is even when the idle state corresponding
>> to this
>> index is disabled or the latency requirement is strict and the
>> exit_latency
>> of the lowest idle state is also not acceptable. Hence this patch
>> fixes this logic in the menu governor by defaulting to an idle state
>> index
>>  of -1 unless any other state is suitable.
> 
> state 0 is defined as polling, and polling ALWAYS should be ok

Hmm.. you are right. This is convincing. There is no need for this patch.

Thanks

Regards
Preeti U Murthy
> 

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