Leaving the Desktop Market

[Nathan Whitehorn]

On 05/03/14 22:29, Adrian Chadd wrote:
> On 3 May 2014 21:52, Allan Jude <freebsd at allanjude.com> wrote:
>
>>> * use cpufreq with some heuristics (like say, only step down to 2/3rd
>>> the frequency if idle) - and document why that decision is made (eg on
>>> CPU X, measuring Y at idle, power consumption was minimal at
>>> frequency=Z.);
>>> * make sure the lower frequencies and tcc kick in if a thermal cutoff
>>> is reached;
>>> * default to using lower Cx states out of the box if they're decided
>>> to not be buggy. There are a few CPUs for which lower C states cause
>>> problems but modernish hardware (say, nehalem and later) should be
>>> fine.
>> According to the wiki, in 9.x and onward there is code that is supposed
>> to detect if the higher Cx states are usable, and not use them if they
>> are not, but I do not know how well this works.
> I'm not sure. I think those who care / know enough just put relevant
> bits into /etc/rc.conf and /boot/loader.conf rather than flipping it
> on by default.
>
> I'm kind of tempted to just flip on Cmax by default and teach powerd
> to not do cpufreq unless there's a thermal issue. Then take a step
> back and see what happens.
>

Please remember that powerd is not x86-only. Other systems (e.g. 
PowerPC) use it in conjunction with cpufreq.

But seriously, let's just pull tcc from GENERIC. I'll do it next week 
unless I hear any objections.
-Nathan