linux-kernel - Re: cpufreq default governor

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Message-ID: <Pine.LNX.4.64.0704241320080.25153@server.thyself>
Date:	Tue, 24 Apr 2007 13:25:30 +0000 (GMT)
From:	William Heimbigner <icxcnika@....tar.cc>
To:	Michal Piotrowski <michal.k.k.piotrowski@...il.com>
cc:	linux-kernel@...r.kernel.org
Subject: Re: cpufreq default governor

On Tue, 24 Apr 2007, Michal Piotrowski wrote:
> On 24/04/07, William Heimbigner <icxcnika@....tar.cc> wrote:
>>  On Tue, 24 Apr 2007, Michal Piotrowski wrote:
>> 
>> >  On 24/04/07, William Heimbigner <icxcnika@....tar.cc> wrote:
>> > >   On Tue, 24 Apr 2007, Michal Piotrowski wrote:
>> > > 
>> > > >   Hi William,
>> > > > 
>> > > >   On 24/04/07, William Heimbigner <icxcnika@....tar.cc> wrote:
>> > > > >    Question: is there some reason that kconfig does not allow for
>> > > > >    default
>> > > > >    governors of conservative/ondemand/powersave?
>> > > > 
>> > > >   Performance?
>> > > > 
>> > > > >    I'm not aware of any reason why one of those governors could not 
>> > > > >    be
>> > > > >    used
>> > > > >    as default.
>> > > > 
>> > > >   My hardware doesn't work properly with ondemand governor. I hear
>> > > >   strange noises when frequency is changed.
>> > > > 
>> > > 
>> > >   That doesn't mean it isn't working, though.
>> > 
>> >  I didn't say that cpufreq ondemand is broken. It's a hardware problem.
>> > 
>> > >   I here weird noises if the cpu
>> > >   is clocked anywhere from 333MHz to 1GHz (sounds like an RD-D2 beeping
>> > >   noises in ultra high pitch?)
>> > 
>> >  Yes, something like that.
>>
>>  Is it actually "not working" though, even at the hardware level?
>
> It works, but for me this sounds are very weird ;)
>
>>  To my
>>  knowledge those noises are normal, and aren't even signs of a harware
>>  problem. I believe it is the natural result of changing frequencies at any
>>  time. If you change frequencies, especially in the low end of available
>>  frequencies, you should hear a very brief noise. A governor such as
>>  ondemand, which is rapidly switching the frequency from say, 333 MHz to
>>  2.66 GHz, is likely to make this much more noticable.
>
> Ok, it might be normal behavior. I might be wrong, but IMO users
> prefer speed and no strange sounds as default setting.

I agree! My suggestion, however, is that if they do want a different 
scheduler as the default, they can choose one.

There are some cases in which this could be very useful. A couple examples 
would be the processor with poor cooling that overheats easily, or a 
laptop with a poor battery.

However, on second thought with regards to Kconfig, would it be feasible 
to have performance always be the default, unless a 
"cpufreqgov=conservative" arguement was specified on the command line?

This would be less susceptible to users complaining that their cpu is 
chirping all of a sudden.

William Heimbigner
icxcnika@....tar.cc
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