Xen devel - Dec 2008 - [PATCH] Change default cpufreq governor from performance to ondemand

Change default cpufreq governor from performance to ondemand

Signed-off-by: Liu, Jinsong <jinsong.liu@intel.com>

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How significant is the performance impact likely to be?

 -- Keir

On 11/12/2008 05:34, "Liu, Jinsong" <jinsong.liu@intel.com>
wrote:
> Change default cpufreq governor from performance to ondemand
> 
> Signed-off-by: Liu, Jinsong <jinsong.liu@intel.com>


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Keir Fraser wrote:
> How significant is the performance impact likely to be?
> 
>  -- Keir
> 
> On 11/12/2008 05:34, "Liu, Jinsong" <jinsong.liu@intel.com>
wrote:
> 
>> Change default cpufreq governor from performance to ondemand
>> 
>> Signed-off-by: Liu, Jinsong <jinsong.liu@intel.com>
Keir,

Sorry, I didn''t speak clear the reason why we change default cpufreq
governor from ''performance'' to ''ondemand''.
We send out user PM interface patch yesterday, at that time the default governor
is ''performance'', which is similar to the default setting of
native linux.
However, since we didn''t send out xenpm tools until now, and
considering people want to test ''ondemand'' governor, we
temporarily set default governor as ''ondemand'', as what we did
recently.
After we send out xenpm tools, we will set default governor as
''performance'' again. At that time, user can use xenpm tool to
change cpufreq governor to ''ondemand'' on-the-fly if he want.

Thanks,
Jinsong
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On 11/12/2008 11:52, "Liu, Jinsong" <jinsong.liu@intel.com>
wrote:
> Sorry, I didn''t speak clear the reason why we change default
cpufreq governor
> from ''performance'' to ''ondemand''.
> We send out user PM interface patch yesterday, at that time the default
> governor is ''performance'', which is similar to the
default setting of native
> linux.
> However, since we didn''t send out xenpm tools until now, and
considering
> people want to test ''ondemand'' governor, we temporarily
set default governor
> as ''ondemand'', as what we did recently.
> After we send out xenpm tools, we will set default governor as
''performance''
> again. At that time, user can use xenpm tool to change cpufreq governor to
> ''ondemand'' on-the-fly if he want.
Perhaps a boot-time option to set the initial default would be better?

 -- Keir



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Keir Fraser wrote:
> On 11/12/2008 11:52, "Liu, Jinsong" <jinsong.liu@intel.com>
wrote:
> 
>> Sorry, I didn''t speak clear the reason why we change default
cpufreq
>> governor from ''performance'' to
''ondemand''.
>> We send out user PM interface patch yesterday, at that time the
>> default governor is ''performance'', which is similar
to the default
>> setting of native linux. However, since we didn''t send out
xenpm
>> tools until now, and considering people want to test
''ondemand''
>> governor, we temporarily set default governor as
''ondemand'', as what
>> we did recently. 
>> After we send out xenpm tools, we will set default governor as
>> ''performance'' again. At that time, user can use xenpm
tool to change
>> cpufreq governor to ''ondemand'' on-the-fly if he want.
> 
> Perhaps a boot-time option to set the initial default would be better?
> 
>  -- Keir
En, in fact we also think this solution, let command line parse to set initial
default governor.
However, it also need user to set at grub, compared with xenpm, seems xenpm tool
is some convenient to user, since by xenpm user can get initial default governor
and change governor on the fly.
It''s my draft thinking, and we can add boot-time option ASAP once you
think needed.

Thanks,
Jinsong
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On 11/12/2008 14:59, "Liu, Jinsong" <jinsong.liu@intel.com>
wrote:
>> Perhaps a boot-time option to set the initial default would be better?
>> 
>>  -- Keir
> 
> En, in fact we also think this solution, let command line parse to set
initial
> default governor.
> However, it also need user to set at grub, compared with xenpm, seems xenpm
> tool is some convenient to user, since by xenpm user can get initial
default
> governor and change governor on the fly.
> It''s my draft thinking, and we can add boot-time option ASAP once
you think
> needed.
Well a boot option would simply be another way to specify the initial
default? I would accept a patch to do that, and I won''t accept your
patch to
temporarily change performance to on_demand. Or we can do nothing, if
actually this isn''t very important. Up to you.

 -- Keir



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Keir Fraser wrote:
> On 11/12/2008 14:59, "Liu, Jinsong" <jinsong.liu@intel.com>
wrote:
> 
>>> Perhaps a boot-time option to set the initial default would be
>>> better? 
>>> 
>>>  -- Keir
>> 
>> En, in fact we also think this solution, let command line parse to
>> set initial default governor. However, it also need user to set at
>> grub, compared with xenpm, seems xenpm tool is some convenient to
>> user, since by xenpm user can get initial default governor and
>> change governor on the fly. 
>> It''s my draft thinking, and we can add boot-time option ASAP
once
>> you think needed.
> 
> Well a boot option would simply be another way to specify the initial
> default? I would accept a patch to do that, and I won''t accept
your
> patch to temporarily change performance to on_demand. Or we can do
> nothing, if actually this isn''t very important. Up to you.
> 
>  -- Keir
> 
> 
> 
> _______________________________________________
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> Xen-devel@lists.xensource.com
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Keir,

Just discuss with Kevin.
Let''s do nothing, and we will send xenpm tool ASAP.

Thanks,
Jinsong
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