Feature #15013
openSpeed Shift - Add Field to control lowest C-State
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Description
Dear pfSense-team,
after updating to 2.7.1 i was curious how well the new speed shift GUI entries work.
In fact after adjusting it to per core and a value of 90, i can see my i3-7100U is able to clock somewhat lower and park the cores more often.
One thing in noticed with the command:
sysctl dev.cpu | grep cx_
is, that my CPU supports C1 and C2, but the lowest c-state setting was set to C1 by default:
dev.cpu.0.cx_method: C1/mwait/hwc C2/mwait/hwc
dev.cpu.0.cx_lowest: C1
By adding the following command to the tunables:
hw.acpi.cpu.cx_lowest = C2
I was able to get the CPU to use its C2-states too. Another XEON-pfsense setup was able to use its C3 states as well, by using the commands stated.
One is able to see the usage of c-states with the following command:
sysctl dev.cpu | grep cx_usage
dev.cpu.0.cx_usage_counters: 3717721 111658492
dev.cpu.0.cx_usage: 3.22% 96.77% last 294us
Would it be possible to add a new selection-field to the now existing speedshift-gui in order to be able to select the lowest c-state.
May the selectable values can be parsed from the cpus cabability, which is represented by the values of "dev.cpu.0.cx_method".
Thanks in advance.
Best regards
Dieter