Hi all!
Installed DietPie 7.7 on my old Lenovo S10-3 netbook to use it as a wireguarg VPN. Everything seems to be fine, but I noticed that the CPU is running at a low frequency all the time. Intel Atom N455 can run at 1667 MHz, but the “cpu” command shows ~450Mhz current frequency and 1000/1000 min/max. Even if I set the CPU Governor to “performance” and 1000/1667 (min/max), and run the stress test, it keeps showing ~450Mhz current frequency. Any suggestions on how to fix this?
The CPU governor cannot affect the maximum frequency, but is responsible only for scaling between min and max.
When you say 1000/1000 and 1000/1667, does this mean the default min/max in /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq and /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq and you were able to raise the maximum value above its default? These are the limits for the governor which cannot be lower/higher than what the kernel/firmware allows as absolute range. And by default (when you choose “Disabled” in dietpi-config) those limits should match the absolute range 
.
Furthermore strange that the minimum was 1000 MHz but the current frequency was 450 MHz? That shouldn’t be possible. Please try to disable both frequency limits, switch to schedutil governor and then paste the output of cpu here.
/sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq and /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq are set to 1000000, and i cant change it: “[ Error writing lock file ./.scaling_max_freq.swp: Permission denied ]”
Nothing’s changed.
DietPi CPU Info
Use dietpi-config to change CPU / performance options
─────────────────────────────────────────────────────
Architecture | x86_64
Temperature | 56'C : 132'F (Running warm, but safe)
Governor | schedutil
Current Freq Min Freq Max Freq
CPU0 | 497 MHz 1000 MHz 1000 MHz
CPU1 | 496 MHz 1000 MHz 1000 MHz
[ INFO ] DietPi-CPU_info | CPU current frequency, may be affected by this script, due to the processing required to run it.
PS: Made another usb drive and ran it on another old laptop with a C2D T7200, and everything seems fine there. Maybe the problem is that my Lenovo runs without battery, some hardware limitation?
Ah is the intel pstate driver used instead of CPUfreq?
cat /sys/devices/system/cpu/intel_pstate/{min,max}_perf_pct
cat /sys/devices/system/cpu/intel_pstate/no_turbo
ls -l /sys/devices/system/cpu/intel_pstate
Nope 
“No such file or directory”
root@DietPi:/sys/devices/system/cpu# ls
cpu0 cpufreq hotplug kernel_max modalias online power smt vulnerabilities
cpu1 cpuidle isolated microcode offline possible present uevent
Strange, so somehow the CPU frequency is not properly managed by the Linux CPUfreq driver. Can you show:
lsmod
cat /proc/cpuinfo
Yeah, maybe I did something wrong during installation?
root@DietPi:~# lsmod
Module Size Used by
wireguard 90112 0
libchacha20poly1305 16384 1 wireguard
chacha_x86_64 28672 1 libchacha20poly1305
poly1305_x86_64 28672 1 libchacha20poly1305
ip6_udp_tunnel 16384 1 wireguard
udp_tunnel 20480 1 wireguard
libblake2s 16384 1 wireguard
blake2s_x86_64 20480 1 libblake2s
curve25519_x86_64 36864 1 wireguard
libcurve25519_generic 49152 2 curve25519_x86_64,wireguard
libchacha 16384 1 chacha_x86_64
libblake2s_generic 20480 1 blake2s_x86_64
ctr 16384 3
aes_generic 36864 6
libaes 16384 1 aes_generic
crypto_simd 16384 0
cryptd 24576 1 crypto_simd
glue_helper 16384 0
ccm 20480 9
i915 2711552 1
ath9k 139264 0
ath9k_common 20480 1 ath9k
ath9k_hw 487424 2 ath9k_common,ath9k
ath 36864 3 ath9k_common,ath9k,ath9k_hw
mac80211 983040 1 ath9k
cpufreq_ondemand 16384 0
cpufreq_powersave 20480 0
cpufreq_conservative 16384 0
snd_hda_codec_realtek 155648 1
cpufreq_userspace 20480 2
snd_hda_codec_generic 98304 1 snd_hda_codec_realtek
ledtrig_audio 16384 1 snd_hda_codec_generic
snd_hda_intel 57344 0
snd_intel_dspcfg 28672 1 snd_hda_intel
soundwire_intel 45056 1 snd_intel_dspcfg
soundwire_generic_allocation 16384 1 soundwire_intel
snd_soc_core 315392 1 soundwire_intel
drm_kms_helper 278528 1 i915
cfg80211 970752 4 ath9k_common,ath9k,ath,mac80211
snd_compress 32768 1 snd_soc_core
soundwire_cadence 36864 1 soundwire_intel
uvcvideo 114688 0
snd_hda_codec 172032 3 snd_hda_codec_generic,snd_hda_intel,snd_hda_codec_realtek
videobuf2_vmalloc 20480 1 uvcvideo
cec 61440 2 drm_kms_helper,i915
videobuf2_memops 20480 1 videobuf2_vmalloc
snd_hda_core 110592 4 snd_hda_codec_generic,snd_hda_intel,snd_hda_codec,snd_hda_codec_realtek
videobuf2_v4l2 36864 1 uvcvideo
videobuf2_common 65536 2 videobuf2_v4l2,uvcvideo
snd_hwdep 16384 1 snd_hda_codec
drm 618496 3 drm_kms_helper,i915
soundwire_bus 90112 3 soundwire_intel,soundwire_generic_allocation,soundwire_cadence
videodev 286720 3 videobuf2_v4l2,uvcvideo,videobuf2_common
snd_pcm 135168 6 snd_hda_intel,snd_hda_codec,soundwire_intel,snd_compress,snd_soc_core,snd_hda_core
snd_timer 49152 1 snd_pcm
snd 110592 9 snd_hda_codec_generic,snd_hwdep,snd_hda_intel,snd_hda_codec,snd_hda_codec_realtek,snd_timer,snd_compress,snd_soc_core,snd_pcm
sg 36864 0
iTCO_wdt 16384 0
coretemp 20480 0
mc 61440 4 videodev,videobuf2_v4l2,uvcvideo,videobuf2_common
evdev 28672 0
joydev 28672 0
intel_pmc_bxt 16384 1 iTCO_wdt
libarc4 16384 1 mac80211
iTCO_vendor_support 16384 1 iTCO_wdt
soundcore 16384 1 snd
watchdog 28672 1 iTCO_wdt
serio_raw 20480 0
at24 24576 0
wmi_bmof 16384 0
pcspkr 16384 0
i2c_algo_bit 16384 1 i915
nft_counter 16384 1
ideapad_laptop 24576 0
sparse_keymap 16384 1 ideapad_laptop
rfkill 28672 4 ideapad_laptop,cfg80211
nft_chain_nat 16384 4
xt_MASQUERADE 20480 1
ac 16384 0
acpi_cpufreq 32768 1
nf_nat 53248 2 nft_chain_nat,xt_MASQUERADE
button 24576 0
nf_conntrack 176128 2 nf_nat,xt_MASQUERADE
nf_defrag_ipv6 24576 1 nf_conntrack
nf_defrag_ipv4 16384 1 nf_conntrack
xt_comment 16384 1
nft_compat 20480 2
nf_tables 245760 7 nft_compat,nft_counter,nft_chain_nat
libcrc32c 16384 3 nf_conntrack,nf_nat,nf_tables
nfnetlink 16384 2 nft_compat,nf_tables
fuse 167936 1
configfs 57344 1
ip_tables 32768 0
x_tables 53248 4 nft_compat,xt_comment,ip_tables,xt_MASQUERADE
autofs4 53248 2
ext4 921600 1
crc16 16384 1 ext4
mbcache 16384 1 ext4
jbd2 151552 1 ext4
crc32c_generic 16384 3
sd_mod 61440 2
t10_pi 16384 1 sd_mod
crc_t10dif 20480 1 t10_pi
crct10dif_generic 16384 1
crct10dif_common 16384 2 crct10dif_generic,crc_t10dif
ums_realtek 24576 1
uas 32768 0
usb_storage 81920 2 uas,ums_realtek
ahci 40960 0
libahci 45056 1 ahci
libata 290816 2 libahci,ahci
uhci_hcd 53248 0
ehci_pci 20480 0
ehci_hcd 98304 1 ehci_pci
scsi_mod 262144 5 sd_mod,usb_storage,uas,libata,sg
psmouse 184320 0
usbcore 323584 7 ehci_pci,usb_storage,uvcvideo,ehci_hcd,uas,ums_realtek,uhci_hcd r8169 102400 0
i2c_i801 32768 0
i2c_smbus 20480 1 i2c_i801
lpc_ich 28672 0
realtek 24576 1
mdio_devres 16384 1 r8169
libphy 151552 3 r8169,mdio_devres,realtek
usb_common 16384 4 usbcore,uvcvideo,ehci_hcd,uhci_hcd
wmi 36864 2 wmi_bmof,ideapad_laptop
battery 20480 0
video 53248 2 ideapad_laptop,i915
root@DietPi:~# cat /proc/cpuinfo
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 28
model name : Intel(R) Atom(TM) CPU N455 @ 1.66GHz
stepping : 10
microcode : 0x107
cpu MHz : 495.811
cache size : 512 KB
physical id : 0
siblings : 2
core id : 0
cpu cores : 1
apicid : 0
initial apicid : 0
fpu : yes
fpu_exception : yes
cpuid level : 10
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm constant_tsc arch_perfmon pebs bts rep_good nopl cpuid aperfmperf pni dtes64 monitor ds_cpl est tm2 ssse3 cx16 xtpr pdcm movbe lahf_lm dtherm bugs :
bogomips : 3325.04
clflush size : 64
cache_alignment : 64
address sizes : 32 bits physical, 48 bits virtual
power management:
processor : 1
vendor_id : GenuineIntel
cpu family : 6
model : 28
model name : Intel(R) Atom(TM) CPU N455 @ 1.66GHz
stepping : 10
microcode : 0x107
cpu MHz : 494.601
cache size : 512 KB
physical id : 0
siblings : 2
core id : 0
cpu cores : 1
apicid : 1
initial apicid : 1
fpu : yes
fpu_exception : yes
cpuid level : 10
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm constant_tsc arch_perfmon pebs bts rep_good nopl cpuid aperfmperf pni dtes64 monitor ds_cpl est tm2 ssse3 cx16 xtpr pdcm movbe lahf_lm dtherm bugs :
bogomips : 3325.04
clflush size : 64
cache_alignment : 64
address sizes : 32 bits physical, 48 bits virtual
power management:
I don’t think that you made something wrong, but that this Atom CPU is not well supported by the current Linux CPUfreq driver/scheduler. Wouldn’t be the first time we see issues with an Atom.
So the CPU scheduler is acpi_cpufreq, which is pretty much the default indeed. Can you try:
modprobe pcc-cpufreq
modprobe -r acpi-cpufreq
modprobe: FATAL: Module acpi_cpufreq is in use.
it looks like I need to disable acpi_cpufreq first?
Try it like that:
modprobe -rf acpi-cpufreq
modprobe pcc-cpufreq
same error
Like I said, I’m using an old laptop and it’s battery free. It seems that the low CPU frequency is a hardware limitation when the laptop can’t charge the battery (my case). Maybe there is a software solution to solve this problem?
I think I’ve found the cause. CPU frequency starts dropping when the temperature rises above 48 degrees, but the fan in the laptop begins to run only after 60 degrees. So I either need to get the fan running before the processor starts to heat up, or disable BD_Prochot.
Ah this makes sense. Does cpu also show a higher maximum frequency before it gets hot?
Yes. Until the processor temperature rises to 47 degrees Celsius, everything works as it should. When the temperature rises above 48, I literally watch the CPU frequency drop to 450.
Update:
pwmconfig: There are no pwm-capable sensor modules installed
So, i tried to boot from ssd with win7 to update the bios, but accidently forgot to change boot order and booted from SD with DietPi. And guess what??? CPU frequency not dropping down any more. To check that is really true, i have installed old 80GB hdd and again booted on to DietPi, and CPU frequency was totally fine.
What was that, weird bug?
Murphy’s law 
Lol, strange indeed. Great that it works now.