Re: [PATCH v3 1/3] cpufreq: Add boost frequency support in core

From: Viresh Kumar
Date: Mon Jun 17 2013 - 09:10:58 EST

On 17 June 2013 15:28, Lukasz Majewski <l.majewski@xxxxxxxxxxx> wrote:
> Yes. But I don't want to hardcode anything. Especially starting CPU
> number.

There is nothing wrong with it. for_each_online_cpu() is good enough
on these cases.

>> > How one can control the boost? I'm now (on my setup) using thermal
>> > subsystem. I set proper trip points and when one of them is met,
>> > then boost is disabled. Moreover the thermal governor (stepwise)
>> > also reduces frequency.
>> >
>> > It works stable with v3.10 (with 3.8 there were some bugs - now they
>> > are fixed).
>> >
>> >
>> > The core acpi-cpufreq.c code hadn't been changed by me, so I assume
>> > that it will work as before.
>> That should adapt your patch in your patchset.


>> From sysfs?? I thought we are going to have some automatic control
>> of this stuff from inside kernel.
> From sysfs I just enable the boost. I do not order from userpace the
> cpufreq to run with a particular (boosted) frequency.
> When I enable boost - I ask (politely) the cpufreq core to reevaluate
> policies and when applicable increase policy->max.
> Then governor can use this new frequencies for normal operation.

So, with your current patchset in, ondemand or conservative governors
will start using boost frequencies. Which might burn your chip.
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