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From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: arun@linux.vnet.ibm.com
Cc: Gautham R Shenoy <ego@in.ibm.com>,
	"Pallipadi, Venkatesh" <venkatesh.pallipadi@intel.com>,
	linux-kernel@vger.kernel.org, Paul Mackerras <paulus@samba.org>,
	Ingo Molnar <mingo@elte.hu>,
	linuxppc-dev@lists.ozlabs.org,
	Balbir Singh <balbir@linux.vnet.ibm.com>
Subject: Re: [PATCH 2/4]: CPUIDLE: Introduce architecture independent cpuidle_pm_idle in drivers/cpuidle/cpuidle.c
Date: Fri, 28 Aug 2009 08:40:11 +0200	[thread overview]
Message-ID: <1251441611.18584.112.camel@twins> (raw)
In-Reply-To: <20090828044901.GA10283@linux.vnet.ibm.com>

On Fri, 2009-08-28 at 10:19 +0530, Arun R Bharadwaj wrote:
> 
> 
> This only does the job of picking the right idle loop for current
> latency and power requirement. This is already done in ladder/menu
> governors under the routines menu_select()/ladder_select().
> I'm not sure whats the purpose of it here.

I can't seem to find ladder_select() but menu_select() doesn't manage
pm_idle and its not clear what it does manage.

> Here we are only concerned about the main idle loop, which is
> pm_idle/ppc_md.power_save. After setting the main idle loop to
> cpuidle_pm_idle, that would call cpuidle_idle_call() which would do
> the job of picking the right low level idle loop based on latency and
> other requirements.

It also gets pm_idle unexported and avoids anybody directly tinkering
with the function pointer, _that_ is the whole goal.

pm_idle is it exists today, and the whole cpuidle_{un,}install*() is
utter crap. It relies on unmanaged access to this function pointer.

/me stop looking at drivers/cpuidle/, convoluted mess that is, shame on
you for wanting to have anything to do with it.

WARNING: multiple messages have this Message-ID (diff)
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: arun@linux.vnet.ibm.com
Cc: Joel Schopp <jschopp@austin.ibm.com>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>, Ingo Molnar <mingo@elte.hu>,
	Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>,
	Dipankar Sarma <dipankar@in.ibm.com>,
	Balbir Singh <balbir@linux.vnet.ibm.com>,
	Gautham R Shenoy <ego@in.ibm.com>,
	"Pallipadi, Venkatesh" <venkatesh.pallipadi@intel.com>,
	linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH 2/4]: CPUIDLE: Introduce architecture independent cpuidle_pm_idle in drivers/cpuidle/cpuidle.c
Date: Fri, 28 Aug 2009 08:40:11 +0200	[thread overview]
Message-ID: <1251441611.18584.112.camel@twins> (raw)
In-Reply-To: <20090828044901.GA10283@linux.vnet.ibm.com>

On Fri, 2009-08-28 at 10:19 +0530, Arun R Bharadwaj wrote:
> 
> 
> This only does the job of picking the right idle loop for current
> latency and power requirement. This is already done in ladder/menu
> governors under the routines menu_select()/ladder_select().
> I'm not sure whats the purpose of it here.

I can't seem to find ladder_select() but menu_select() doesn't manage
pm_idle and its not clear what it does manage.

> Here we are only concerned about the main idle loop, which is
> pm_idle/ppc_md.power_save. After setting the main idle loop to
> cpuidle_pm_idle, that would call cpuidle_idle_call() which would do
> the job of picking the right low level idle loop based on latency and
> other requirements.

It also gets pm_idle unexported and avoids anybody directly tinkering
with the function pointer, _that_ is the whole goal.

pm_idle is it exists today, and the whole cpuidle_{un,}install*() is
utter crap. It relies on unmanaged access to this function pointer.

/me stop looking at drivers/cpuidle/, convoluted mess that is, shame on
you for wanting to have anything to do with it.




  reply	other threads:[~2009-08-28  6:46 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-08-27 11:49 [v3 PATCH 0/4]: CPUIDLE/POWER: Introducing cpuidle infrastructure to POWER Arun R Bharadwaj
2009-08-27 11:49 ` Arun R Bharadwaj
2009-08-27 11:51 ` [PATCH 1/4]: CPUIDLE/POWER: Enable cpuidle for pSeries Arun R Bharadwaj
2009-08-27 11:51   ` Arun R Bharadwaj
2009-08-27 11:53 ` [PATCH 2/4]: CPUIDLE: Introduce architecture independent cpuidle_pm_idle in drivers/cpuidle/cpuidle.c Arun R Bharadwaj
2009-08-27 11:53   ` Arun R Bharadwaj
2009-08-27 12:53   ` Peter Zijlstra
2009-08-27 12:53     ` Peter Zijlstra
2009-08-27 21:28     ` Benjamin Herrenschmidt
2009-08-27 21:28       ` Benjamin Herrenschmidt
2009-08-28  4:49     ` Arun R Bharadwaj
2009-08-28  4:49       ` Arun R Bharadwaj
2009-08-28  6:40       ` Peter Zijlstra [this message]
2009-08-28  6:40         ` Peter Zijlstra
2009-08-28  6:14     ` Arun R Bharadwaj
2009-08-28  6:14       ` Arun R Bharadwaj
2009-08-28  6:48       ` Peter Zijlstra
2009-08-28  6:48         ` Peter Zijlstra
2009-08-28  6:59         ` Balbir Singh
2009-08-28  6:59           ` Balbir Singh
2009-08-28  7:01         ` Peter Zijlstra
2009-08-28  7:01           ` Peter Zijlstra
2009-08-28  8:19           ` Vaidyanathan Srinivasan
2009-08-28  8:19             ` Vaidyanathan Srinivasan
2009-08-28  6:43     ` Arun R Bharadwaj
2009-08-28  6:43       ` Arun R Bharadwaj
2009-08-27 11:55 ` [PATCH 3/4]: ACPI/ARM: Register for cpuidle_pm_idle in drivers/acpi/processor_idle.c and arch/arm/mach-kirkwood/cpuidle.c Arun R Bharadwaj
2009-08-27 11:55   ` Arun R Bharadwaj
2009-08-27 11:57 ` [PATCH 4/4]: CPUIDLE/POWER: Implement Pseries Processor Idle module Arun R Bharadwaj
2009-08-27 11:57   ` Arun R Bharadwaj

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