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 Post subject: CPUDYN frequency scaling for ppc
PostPosted: 05 Mar 2009, 19:24 
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Joined: 21 Jan 2009, 08:58
Posts: 31
CPUDYN has been the only reliable way for me to control cpu frequency scaling on my ppc box. Normally I compile it from the /x86/opt ports, but wonder if it should be copied to the /ppc ports directory?

(It was developed by a ppc user!)

All my attempts to use cpufreq-utils to control scaling have failed (error console shows too long a latency switch time, and the system just reverts to full-speed).

Therefore, I have found that using cpudyn has worked just fine in all cases. cat /proc/cpuinfo is happy. I just add "cpudynd" to the SERVICES= stanza in /etc/rc.conf. No quotes. It is a daemon, so don't forget the "d". Normally I leave this as the last entry (unless one uses alsa which likes to go last)

Cpudyn is a little long in the tooth, and may not be the best bet for smp, as it scales multiple cpus up and down at the same rate, but perhaps that may be better than nothing for some. At least on single-cpu systems, it works just fine.

As measured by a wattmeter on my AC outlet, when idle my system runs at 900mhz (vs 1.8ghz full speed) , and actually saves about 10 watts of power. (A non-blinking cursor was also measured to save about 2 watts - I didn't believe it until I measured it.)

Since cpudyn only uses just the lowest and fastest speeds, the switching latency is very small, and has been useful when doing audio editing or other tasks that need low-latency switching.


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 Post subject: Re: CPUDYN frequency scaling for ppc
PostPosted: 05 Mar 2009, 20:21 
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Joined: 03 Jan 2008, 18:12
Posts: 40
Location: Italy
stream303 wrote:
CPUDYN has been the only reliable way for me to control cpu frequency scaling on my ppc box. Normally I compile it from the /x86/opt ports, but wonder if it should be copied to the /ppc ports directory?


Well the answer is simple: we never merely copy ports from x86 to ppc (it would be an useless redundancy), we add only ports that needs some change in our tree. ppc users can, usually, use ports from x86 if they aren't in ppc's repository.


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 Post subject:
PostPosted: 06 Mar 2009, 20:26 
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Joined: 21 Jan 2009, 08:58
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No problem really. Plus, you're kind of busy with other issues. :) (thanks btw..)

I have seen duplicates like Firefox in X86 and PPC, and wondered what the difference was? When I build the ppc version, it just compiles really quickly, much faster than x86 although I would have thought they would take the same amount of time.

I'll dig into the Pkgfiles and see what the difference is - I'm missing something for sure.


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 Post subject:
PostPosted: 09 Mar 2009, 12:21 
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Joined: 17 Dec 2005, 14:31
Posts: 310
Location: Italy
anyway we host a cpudyn source's copy on our own ftp server too.


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