> From: Bruce Cran <bruce_at_cran.org.uk> > Date: Wed, 6 Oct 2010 07:18:38 +0100 > Sender: owner-freebsd-current_at_freebsd.org > > On Wednesday 06 October 2010 03:02:36 Alexander Kojevnikov wrote: > > > This variable allows to underclock the CPU, which is useful when > > building quiet or low-power systems. > > You can use the new -m and -M switches to powerd to control the minimum and > maximum frequencies instead. Ack! Did this really make it into the code? This is NOT the answer. the answer is to get rid of the useless CPU throttling and TCC which is the real cause of this. Neither of these methods was designed as a power management mechanism. They were designed to keep the processor from over-heating. They both can do what they were designed for quite well, but they can provide only very limited power savings and can actually result in higher power consumption in some cases. (I reported on my research into this several years ago, but the definitive work was done by mav_at_ and can be read on the FreeBSD wiki at http://wiki.freebsd.org/TuningPowerConsumption If we would just get rid of this (or at least turn it off by default), this whole problems requiring -m would go away. (I can see real use for -M, though.) -- R. Kevin Oberman, Network Engineer Energy Sciences Network (ESnet) Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab) E-mail: oberman_at_es.net Phone: +1 510 486-8634 Key fingerprint:059B 2DDF 031C 9BA3 14A4 EADA 927D EBB3 987B 3751Received on Wed Oct 06 2010 - 13:30:02 UTC
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