September 24, 201510 yr I just put in a core2duo to replace my older celeron. (until I can upgrade the whole system) It has two cores with speedstep. I'm trying to figure out how it determines to change the speed? The dashboard has both cores at 1200MHz at idle and rams them up to 1700MHz under load (parity test) I think my cpu is capable of 2300MHz? Why didn't it go to 2300? can I set the min to be lower than 1200? like maybe 800MHz? Where are these things set? Thanks, Jim
September 28, 201510 yr Author Ok.. I had the bios specifically slow down the CPU. I did that because I didn't need the HP and to save power. But now with V6 it seems I DO need the HP! So I bumped it up to the default. So my question still stands! How does The kernel decide what the fastest and slowest speeds are for CPU? Right now there are two speeds, 2.5G and 1.6G I'd like to slow down even further. How do I do this? Thanks, Jim
September 28, 201510 yr Telnet/SSH into your server, execute the command below: cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies It should report back what frequencies are availalbe for the governor to use, for example, on my cpu: root@Tower:~# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies 3200000 2800000 2300000 1800000 1400000 root@Tower:~# The values are in Khz, divide the value by 10^6 to get GHz. Those are the speed 'steps' your processor is capable of.
September 28, 201510 yr Author I only get two? Does that mean my processor can only do a fast and a slow? How does it get these defaults?
September 29, 201510 yr I only get two? Does that mean my processor can only do a fast and a slow? How does it get these defaults? From BIOS/CPU. Verify C1E is enabled in BIOS. What CPU do you have and what motherboard?
September 29, 201510 yr Also following along - I'm in the same boat and want to idle at the lowest power consumption possible (intel Xeon Gainestown) - do you have a recommendation for general bios settings? Right now I see: "2801000 2800000 2667000 2533000 2400000 2267000 2133000 2000000 1867000 1733000 1600000" and I do idle at 1600000 - but this is still way too high.
September 29, 201510 yr The avaialble multipliers for EIST are set by the CPU/BIOS. If all CStates are enabled in BIOS (C1, C3, C6, etc.) then you have done what you can do as far as minumum clock while idle. There are ways to keep it at idle longer before ramping up for a load, but depends on what you are after by doing so and wheather or not it is a true benefit.
September 29, 201510 yr Author I guess 6x is the lowest multiplier... So I'm stuck with 1.6G as my lowest cpu freq unless I change my clock to something slower..
September 29, 201510 yr I tried to run this on a xeon e3-1231v3 and got an error. "scaling_available_frequencies" does not exist.
September 30, 201510 yr Might not have Speed Step and/or C1, C3, C6 CStates enabled in BIOS. Telnet/SSH to server and run cpufreq-info The output will be per core of the CPU and will tell you the capabilities and what is currently active. Example for mine, 1 of 8 cores: cpufrequtils 008: cpufreq-info (C) Dominik Brodowski 2004-2009 Report errors and bugs to [email protected], please. analyzing CPU 0: driver: acpi-cpufreq CPUs which run at the same hardware frequency: 0 CPUs which need to have their frequency coordinated by software: 0 maximum transition latency: 4.0 us. hardware limits: 1.40 GHz - 3.20 GHz available frequency steps: 3.20 GHz, 2.80 GHz, 2.30 GHz, 1.80 GHz, 1.40 GHz available cpufreq governors: conservative, userspace, powersave, ondemand, performance current policy: frequency should be within 1.40 GHz and 3.20 GHz. The governor "ondemand" may decide which speed to use within this range. current CPU frequency is 1.40 GHz (asserted by call to hardware). cpufreq stats: 3.20 GHz:1.37%, 2.80 GHz:0.75%, 2.30 GHz:1.43%, 1.80 GHz:6.30%, 1.40 GHz:90.15% (464671) If no governor is active then check BIOS and enable Speed Step and the CStates, should be in the CPU config in BIOS, assuming you want to enable it.
September 30, 201510 yr the output of cpufreq-info for me (Xeon E3-1231v3 is (1 of : cpufrequtils 008: cpufreq-info (C) Dominik Brodowski 2004-2009 Report errors and bugs to [email protected], please. 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: 0.97 ms. hardware limits: 800 MHz - 3.80 GHz available cpufreq governors: performance, powersave current policy: frequency should be within 800 MHz and 3.80 GHz. The governor "powersave" may decide which speed to use within this range. current CPU frequency is 3.42 GHz (asserted by call to hardware). What does it mean? I have no output for "available frequency steps" and no "cpufreq stats".
September 30, 201510 yr the output of cpufreq-info for me (Xeon E3-1231v3 is (1 of : cpufrequtils 008: cpufreq-info (C) Dominik Brodowski 2004-2009 Report errors and bugs to [email protected], please. 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: 0.97 ms. hardware limits: 800 MHz - 3.80 GHz available cpufreq governors: performance, powersave current policy: frequency should be within 800 MHz and 3.80 GHz. The governor "powersave" may decide which speed to use within this range. current CPU frequency is 3.42 GHz (asserted by call to hardware). What does it mean? I have no output for "available frequency steps" and no "cpufreq stats". The governor in use is powersave which means you only have one speed. The lowest speed is all that is available.
September 30, 201510 yr the output of cpufreq-info for me (Xeon E3-1231v3 is (1 of : cpufrequtils 008: cpufreq-info (C) Dominik Brodowski 2004-2009 Report errors and bugs to [email protected], please. 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: 0.97 ms. hardware limits: 800 MHz - 3.80 GHz available cpufreq governors: performance, powersave current policy: frequency should be within 800 MHz and 3.80 GHz. The governor "powersave" may decide which speed to use within this range. current CPU frequency is 3.42 GHz (asserted by call to hardware). What does it mean? I have no output for "available frequency steps" and no "cpufreq stats". The governor in use is powersave which means you only have one speed. The lowest speed is all that is available. But I see the cpu running at 3400 and 3800 and between and lower. How can i change the governor?
September 30, 201510 yr the output of cpufreq-info for me (Xeon E3-1231v3 is (1 of : cpufrequtils 008: cpufreq-info (C) Dominik Brodowski 2004-2009 Report errors and bugs to [email protected], please. 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: 0.97 ms. hardware limits: 800 MHz - 3.80 GHz available cpufreq governors: performance, powersave current policy: frequency should be within 800 MHz and 3.80 GHz. The governor "powersave" may decide which speed to use within this range. current CPU frequency is 3.42 GHz (asserted by call to hardware). What does it mean? I have no output for "available frequency steps" and no "cpufreq stats". The governor in use is powersave which means you only have one speed. The lowest speed is all that is available. But I see the cpu running at 3400 and 3800 and between and lower. How can i change the governor? Your E3 Xeon using the Intel_pstate driver only has performance and powersave available, but powersave on this cpu does scale as you see. The governor in use is probably the best available for that cpu as the Intel config will most likely be better than switching to acpi driver.
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