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[20090507] Throttling the CPU to reduce fan noise
On netbsd-users, Cem Kayali has posted a script to adjust the CPU frequency according to the system temperature, and thus reduce fan noise. This is different from pkgsrc's estd, which just adjusts the CPU speed according to the system load, so it's quite the contrary. Cem uses the envstat(4) framework to determine CPU temperature, and then slows the CPU down with sysctl(1).

An alternative approach was suggested by Jeremy Reed, which hints at the powerd(8) script hooks that can be set to act on corresponting ACPI Thermal Zone (acpitz) events. See Jeremy Reed's blog posting for a few more ideas, plus a hint that this may become documented even better in the future.

While there: At his website, Jeremy has a number of open questions around NetBSD, and I guess answering them would be good for mankind. Any takers?

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