After upgrading my IPF HW to Intel Celeron(R) CPU 3867U @ 1.80GHz, it seems my CPU frequency graph appears upside-down. I’m running Core 155. I switched back to previous HW and things looked normal again. Could this be some peculiar weirdness of the 3867U processor? Please note other indications of usage and load are quite low – it is just the CPU frequency graph that seems upside-down. See attached image.
Hey @cbrown, at first I was not sure what you meant. I had to read your post a few times.
Your CPU frequency graph appears to be quite normal, at least for your specific CPU. Both cores seems to run at 1,8 GHz most of the time, only lowering the frequency at times (to about 1,6 GHz).
This behavior could easily be normal for that particular CPU, at least with the default CPU governor settings.
Thanks for your reply, @cybermaze. Every other processor I have seen has shown a generally lower freq most of the time with the spikes to max freq only occurring occasionally.
Connect to your IPFire box using ssh and issue the command:
cpufreq-info
You will get information back, like which governor is set for each core (should be “performance”) and will also report a frequency range for each core.
My IPFire box uses an Intel Core i3-3220 CPU and I can see that:
current policy: frequency should be within 1.60 GHz and 3.30 GHz.
The governor “performance” may decide which speed to use
within this range.
analyzing CPU 0:
driver: intel_pstate
CPUs which run at the same hardware frequency: 0
CPUs which need to have their frequency coordinated by software: 0
maximum transition latency: 4294.55 ms.
hardware limits: 400 MHz - 1.80 GHz
available cpufreq governors: performance, powersave
current policy: frequency should be within 400 MHz and 1.80 GHz.
The governor “performance” may decide which speed to use
within this range.
current CPU frequency is 1.79 GHz.
analyzing CPU 1:
driver: intel_pstate
CPUs which run at the same hardware frequency: 1
CPUs which need to have their frequency coordinated by software: 1
maximum transition latency: 4294.55 ms.
hardware limits: 400 MHz - 1.80 GHz
available cpufreq governors: performance, powersave
current policy: frequency should be within 400 MHz and 1.80 GHz.
The governor “performance” may decide which speed to use
within this range.
current CPU frequency is 1.80 GHz.
Do you see anything particularly interesting or unusual here?
I changed the governor setting to powersave and now the graph is beginning to look more as I would have expected – both CPUs cruising along mostly @ 900 Mhz
Even if the load is relatively low, it can still make sense to run the CPU at a relatively high speed. This makes the system seem more “responsive”, as lowering frequency raises the latency (in this case the time it takes for network packets to be passed through IPFire).
There is no objectively “right” or “wrong” here, rather it is a question of prioritizing.
Is high speed/low latency most important? Use the “performance” governor.
Is saving power most important? Use the “powersave” governor.
Thanks again for the reply. Latency does not appear to be an issue (no complaints yet since switching to powersave). I am more concerned about thermal / heat. My box is passively cooled and the facility’s climate control can be kind of wonky (particularly when outside weather here can peak over 46°C )
