On 05/04/14 10:05, Allan Jude wrote:
On 2014-05-04 11:47, Allan Jude wrote:
On 2014-05-04 10:28, Matthias Apitz wrote:
El día Saturday, May 03, 2014 a las 04:59:48PM -0700, Kevin Oberman escribió:

On Sat, May 3, 2014 at 1:25 PM, Adrian Chadd <adr...@freebsd.org> wrote:

Set it to the lowest available Cx state that you see in dev.cpu.0 .

Available is not required. Set it to C8. That guarantees that you will use
the lowest available. The correct incantation in rc.conf is "Cmax".

But, unless you want laggy performance, you will probably also want:
in /boot/loader.conf. Low Cx states and TCC/throttling simply don't mix
well and TCC is not effective, as mentioned earlier in this thread.
Re/ powerd I have in /etc/rc.conf:

# powerd
powerd_flags="-a max -b adp"

(and the additional hint.* in /boot/loader.conf as well). Which process
'performance_cx_lowest' and 'economy_cx_lowest' target exactly as config



In a pretty unscientific test on my laptop (Lenovo T530 with Intel i5
3320M), setting hw.acpi.cpu.cx_lowest=C8 lowered power consumption at
idle by about 3 watts, which adds about 30-45 minutes to my battery life
during conservative usage.

Using PCBSD 10, so hint.acpi_throttle.0.disabled=1 was already set
(apparently solves some issue with powerd on some AMD systems)

I have added hint.p4tcc.0.disabled=1 but not sure where to expect to see
a difference.

I see the difference now, with the p4tcc stuff disabled, the lowest
cpufreq is now 1200mhz instead of 150mhz

I just set the default for acpi_throttle and p4tcc in HEAD to disabled by adding these line to the default /boot/device.hints. If you want them back, editing your device.hints will restore them. This can be reverted if many people want throttling enabled by default, but all I have heard so far -- and for the past many years -- is a unanimous chorus to turn it off.
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