Arch Linux

cugovidise

Member

Registered: 2016-07-11

Posts: 2

Cpu is not working full speed.

Hello guys,

I have an AMD FX8300, it says on the box turbo core up to 4.2GHz. When I boot into windows, I scales up to 4.2GHz when needed. In linux it only scales up to 3.3GHz.

I added ignore ppc line to grub, it seem to be working fine. I also set to ignore_tpc to 1.

[root@mbp mbp]# cat /sys/module/processor/parameters/ignore_tpc 
1
[root@mbp mbp]# cat /sys/module/processor/parameters/ignore_ppc 
1

[root@mbp mbp]# cpupower frequency-info 
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 - 3.30 GHz
  available frequency steps:  3.30 GHz, 2.90 GHz, 2.40 GHz, 1.90 GHz, 1.40 GHz
  available cpufreq governors: ondemand performance
  current policy: frequency should be within 1.40 GHz and 3.30 GHz.
                  The governor "ondemand" may decide which speed to use
                  within this range.
  current CPU frequency: 1.40 GHz (asserted by call to hardware)
  boost state support:
    Supported: yes
    Active: yes
    Boost States: 2
    Total States: 7
    Pstate-Pb0: 4200MHz (boost state)
    Pstate-Pb1: 3600MHz (boost state)
    Pstate-P0:  3300MHz
    Pstate-P1:  2900MHz
    Pstate-P2:  2400MHz
    Pstate-P3:  1900MHz
    Pstate-P4:  1400MHz

Cpu still does not scale over 3.3GHz. (Under stress test ) . Try to set the variable by hand.

[root@mbp mbp]# cat  /sys/devices/system/cpu/cpu7/cpufreq/scaling_max_freq 
3300000
[root@mbp mbp]# echo 4200000 >  /sys/devices/system/cpu/cpu7/cpufreq/scaling_max_freq 
[root@mbp mbp]# cat  /sys/devices/system/cpu/cpu7/cpufreq/scaling_max_freq 
3300000
[root@mbp mbp]# echo 2200000 >  /sys/devices/system/cpu/cpu7/cpufreq/scaling_max_freq 
[root@mbp mbp]# cat  /sys/devices/system/cpu/cpu7/cpufreq/scaling_max_freq 
2200000

For some reason, it gave me a permission error when I first tried to edit it with nano. Second time nano worked and saved fine. But something seems to be reverting it back.

[root@mbp mbp]# fuser  /sys/devices/system/cpu/cpu7/cpufreq/scaling_max_freq 
[root@mbp mbp]# lsof  /sys/devices/system/cpu/cpu7/cpufreq/scaling_max_freq 
#both returned empty.

Lets try cpupower.

[root@mbp mbp]# cpupower frequency-set -f 4.20GHz
Setting cpu: 0
Setting cpu: 1
Setting cpu: 2
Setting cpu: 3
Setting cpu: 4
Setting cpu: 5
Setting cpu: 6
Setting cpu: 7
[root@mbp mbp]# stress --cpu 8 --timeout 160
stress: info: [9214] dispatching hogs: 8 cpu, 0 io, 0 vm, 0 hdd
^Z
[1]+  Stopped                 stress --cpu 8 --timeout 160
[root@mbp mbp]# bg
[1]+ stress --cpu 8 --timeout 160 &
[root@mbp mbp]# cpupower monitor
    |Mperf               || Idle_Stats         
CPU | C0   | Cx   | Freq || POLL | C1   | C2   
   0| 99.99|  0.01|  3313||  0.00|  0.00|  0.00
   1| 99.99|  0.01|  3313||  0.00|  0.00|  0.00
   2| 99.99|  0.01|  3313||  0.00|  0.00|  0.00
   3| 99.99|  0.01|  3314||  0.00|  0.00|  0.00
   4| 99.99|  0.01|  3313||  0.00|  0.00|  0.00
   5| 99.99|  0.01|  3313||  0.00|  0.00|  0.00
   6| 99.99|  0.01|  3313||  0.00|  0.00|  0.00
   7| 99.99|  0.01|  3313||  0.00|  0.00|  0.00
[root@mbp mbp]# killall stress
[1]+  Terminated              stress --cpu 8 --timeout 160

Still nothing.

I also have no idea why there is such a limitation by the bios. I have 600W PSU which is more than enought for all my hardware. All the OC settings in bios are set to auto(default option). All the similar cases on google are about notebooks with bad batteries or power bricks.

Note: tried all steps with both default, zen and ck kernels. Worked on none.

Last edited by cugovidise (2016-07-11 21:02:35)

mich41

Member

Registered: 2012-06-22

Posts: 796

Re: Cpu is not working full speed.

Forget CPUFreq, turbo is handled by hardware. And hardware uses it only when a small number of cores is loaded, while you are loading all of them.

cugovidise

Member

Registered: 2016-07-11

Posts: 2

Re: Cpu is not working full speed.

*facepalm*

Thanks for the info.

Last edited by cugovidise (2016-07-12 13:31:56)

Purgator

Member

Registered: 2016-03-02

Posts: 102

Re: Cpu is not working full speed.

Your stress test on windows seems sux a bit ^^ As mich41 said it's about turbo which activate when not all cores are used. You can desactivate that turbo in the bios if you want to o/c
Try OCCT for windows stress test

czg

Member

Registered: 2023-03-19

Posts: 13

Re: Cpu is not working full speed.

I recently also want to turbo core my cpu, and CPUFreq confused me for some time because it always says there is one limit that I misunderstanded that my cpu can't turbo core

Then I found your post and the `stress` make my cpu overclock although CPUFreq not shown turbo freq

$ sudo cpupower frequency-info
analyzing CPU 12:
  driver: acpi-cpufreq
  CPUs which run at the same hardware frequency: 12
  CPUs which need to have their frequency coordinated by software: 12
  maximum transition latency:  Cannot determine or is not supported.
  hardware limits: 1.40 GHz - 2.90 GHz
  available frequency steps:  2.90 GHz, 1.70 GHz, 1.40 GHz
  available cpufreq governors: conservative ondemand userspace powersave performance schedutil
  current policy: frequency should be within 2.90 GHz and 2.90 GHz.
                  The governor "userspace" may decide which speed to use
                  within this range.
  current CPU frequency: 2.90 GHz (asserted by call to hardware)
  boost state support:
    Supported: yes
    Active: yes
    Boost States: 0
    Total States: 3
    Pstate-P0:  2900MHz
    Pstate-P1:  1700MHz
    Pstate-P2:  1400MHz

--------------------------

also from wiki, 'watch cat /sys/devices/system/cpu/cpu[0-9]*/cpufreq/scaling_cur_freq' is helpful to watch freq

2ManyDogs

Forum Fellow

Registered: 2012-01-15

Posts: 4,645

Re: Cpu is not working full speed.

This thread is seven years old and the OP has not been back since 2016. Please do not necrobump.

Closing.