CPUFreqd - a tool for controlling CPU frequencies
This is not new, but I thought someone might be interested anyways. CPUFreqd is a daemon that runs in the background of the system and monitors and controls CPU frequencies. It caught my attention, because I wanted to solve a small problem.
You see, I am running BOINC in the background on my machine. But BOINC will actually use all the compute power it can get, if you don’t set limits in the compute preferences. However I think the limits you can set are rather coarse and don’t really reflect well what I want.
What I want is simple: All the compute I have when I need it. And X% of that compute for BOINC, when I don’t need much compute.
What I don’t want is:
- BOINC suspended when I am using my computer
- BOINC not utilizing all cores of my computer
- BOINCs own crude implementation of X% of compute
In my specific case that means BOINC should utilize all 16 threads my worstation can offer (or as much as I can spare without impeding my own needs) and it should run continuously while my own compute needs are low. While BOINC is running my CPU should be limited to ~3GHz. But when I want all the compute I have for my self, BOINC should be suspended and the CPU should automatically allow frequencies of >4Ghz if possible.
This is where CPUFreqd comes in. You can set different profiles for CPU frequency behavior. And you can set different rules that automatically determine which profile should apply at any given time.
You can read up on how exactly rules and profiles work on cpufreqd’s manpage, but here is what I did to my /etc/cpufreqd.conf:
The first is the profile I want to use for my own compute needs. It uses the powersave governor, so that the cpu will always prefer low frequencies at the cost of slow startup, but thats fine for me.
[Profile]
name=Powersave High
minfreq=30%
maxfreq=100%
policy=powersave
[/Profile]
The next is the BOINC profile. It limits the maximum frequency, but favors the performance governor, which does not make a differece, since BOINCs precesses will pretty much pin the CPU utilization at 100% anyways.
[Profile]
name=Boinc
minfreq=30%
maxfreq=75%
policy=performance
[/Profile]
Next comes the BOINC rule. It is important that this comes first, since order of rules matters during matching. It matches with 2 points when boincmgr is running (change that to ‘boinc’ if you prefer the window closed) and the cpu load is high, giving this rule a higher precedence than other rules.
[Rule]
name=Boinc
programs=boincmgr
cpu_interval=20-100
profile=Boinc
[/Rule]
Last comes the default rule. It matches always with 1 point, being outmatched when BOINC runs but taking precedence otherwise.
[Rule]
name=Default
programs=init
profile=Powersave High
[/Rule]
With these rules, whenever I have boincmgr running, my CPU is limited to ~3GHz (75%), but when I quit BOINC, it permits all possible frequencies. So all I have to do when I want to game or render with Blender or otherwise utilize all the compute of my computer is to close boincmgr and thereby suspeding BOINCs processes. When I switch BOINC back on, my CPU automatically is throttled back to a reasonable level to save a bit on my powerbill and reduce the heating of my room.
Combinded with setting BOINC to use 90% of CPU cores, this gives a very pleasant experience of using my computer while BOINC is running - at least for tasks that don’t demand a lot of compute power, like surfing th web or checking emails. Quitting the BOINC manager and therfore suspending computation however then unleashes all the power my machine can offer.