Arch Linux

partizann

Member

Registered: 2007-07-28

Posts: 9

CPU cannot switch to P0 state

Hello @ll,

(OS: Archlinux current - updated daily )
I recently overclocked my Phenom II 955BE to 4028MHz (19x212MHz),
The problem is that if i start my arch, it scaling well but just between states P1-P3 (2.50 GHz, 2.10 GHz, 800 MHz according to cpufreq - 2.65GHz, 2.23GHz, 848MHz in reality because of higher FSB).
Scaling works perfectly fine if the system is at default clocks.
I have tried to boot with acpi=off parameter - the CPU was running at full speed ~4GHz, but since the acpi also affect the fglrx driver and other things I dont really want to turn it off permanently.
For testing of the CPU speed was used the 7zip benchmark, since the most of the info from cpufreq-info and other sources are not too accurate.

# cpufreq-info -c 0
cpufrequtils 008: cpufreq-info (C) Dominik Brodowski 2004-2009
Report errors and bugs to cpufreq@vger.kernel.org, please.
analyzing CPU 0:
  driver: powernow-k8
  CPUs which run at the same hardware frequency: 0
  CPUs which need to have their frequency coordinated by software: 0
  maximum transition latency: 8.0 us.
  hardware limits: 800 MHz - 3.80 GHz
  available frequency steps: 3.80 GHz, 2.50 GHz, 2.10 GHz, 800 MHz
  available cpufreq governors: ondemand, performance
  current policy: frequency should be within 800 MHz and 3.20 GHz.
                  The governor "performance" may decide which speed to use
                  within this range.
  current CPU frequency is 2.50 GHz (asserted by call to hardware).

What is also strange is the part after the current CPU freq. "asserted by call to hardware"

I have tried to set the higher frequency/Pstate via userspace governor and also via k10ctl, but still the CPU was unable to switch to max performance.

# echo 3800000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq

# echo 3800000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed

# for i in `ls /sys/devices/system/cpu/cpu0/cpufreq/`; do echo -n "$i: "; cat /sys/devices/system/cpu/cpu0/cpufreq/$i ; done
affected_cpus: 0
bios_limit: 3200000
cpb: 0
cpuinfo_cur_freq: 2500000
cpuinfo_max_freq: 3800000
cpuinfo_min_freq: 800000
cpuinfo_transition_latency: 8000
related_cpus: 0
scaling_available_frequencies: 3800000 2500000 2100000 800000 
scaling_available_governors: userspace ondemand performance 
scaling_cur_freq: 2500000
scaling_driver: powernow-k8
scaling_governor: userspace
scaling_max_freq: 3200000
scaling_min_freq: 800000
scaling_setspeed: 2500000

I was unable to set the max_freq or setspeed to 3800000 (4028MHz real)
also "k10ctl 0-3 0" had no effect (should set P0 CPU state)

Have any one some idea or had someone already faced similar problems ??

Here is some more info which can help:

# dmidecode 2.11
SMBIOS 2.5 present.

Handle 0x0004, DMI type 4, 40 bytes
Processor Information
        Socket Designation: AM3
        Type: Central Processor
        Family: Phenom II
        Manufacturer: AMD              
        ID: 43 0F 10 00 FF FB 8B 17
        Signature: Family 16, Model 4, Stepping 3
        Flags:
                FPU (Floating-point unit on-chip)
                VME (Virtual mode extension)
                DE (Debugging extension)
                PSE (Page size extension)
                TSC (Time stamp counter)
                MSR (Model specific registers)
                PAE (Physical address extension)
                MCE (Machine check exception)
                CX8 (CMPXCHG8 instruction supported)
                APIC (On-chip APIC hardware supported)
                SEP (Fast system call)
                MTRR (Memory type range registers)
                PGE (Page global enable)
                MCA (Machine check architecture)
                CMOV (Conditional move instruction supported)
                PAT (Page attribute table)
                PSE-36 (36-bit page size extension)
                CLFSH (CLFLUSH instruction supported)
                MMX (MMX technology supported)
                FXSR (FXSAVE and FXSTOR instructions supported)
                SSE (Streaming SIMD extensions)
                SSE2 (Streaming SIMD extensions 2)
                HTT (Multi-threading)
        Version: AMD Phenom(tm) II X4 955 Processor                  
        Voltage: 1.5 V
        External Clock: 212 MHz
        Max Speed: 3200 MHz
        Current Speed: 4028 MHz
        Status: Populated, Enabled
        Upgrade: Other
        L1 Cache Handle: 0x0005
        L2 Cache Handle: 0x0006
        L3 Cache Handle: 0x0007
        Serial Number: To Be Filled By O.E.M.
        Asset Tag: To Be Filled By O.E.M.
        Part Number: To Be Filled By O.E.M.
        Core Count: 4
        Core Enabled: 4
        Characteristics:
                64-bit capable