Mailinglist Archive: opensuse-kernel (69 mails)

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[opensuse-kernel] kernel & BIOS report (incorrectly?) different current/available speeds for overclocked CPU
  • From: PGNet Dev <pgnet.dev+oskrn@xxxxxxxxx>
  • Date: Sun, 2 Aug 2009 11:27:57 -0700
  • Message-id: <94f2e81e0908021127n6800158awa39e9a04c4ac7097@xxxxxxxxxxxxxx>
i've built up a new openSUSE server on a

mobo: ASUS M3A78-CM, BIOS r1903
cpu: AMD 2.8GHz Phenom II X4 920 (Black)

@ BIOS, i've overclocked the CPU by 33% from 2.8Hz -> 1.33 x 2.*8 = 3.7GHz.

booting to OS, the reported(/available) CPU freq is NOT that which the
BIOS reports.

questions:

(1) is this a bug, or expected behavior for OC'ing?
(2) if a bug, is it in kernel, or BIOS?
(3) if not a bug, how does one monitor _actual_ CPU speed in openSUSE?


details ...

uname -a
Linux server 2.6.27.25-0.1-default #1 SMP 2009-07-01 15:37:09
+0200
x86_64 x86_64 x86_64 GNU/Linux

checking,

cpufreq-info
cpufrequtils 004: cpufreq-info (C) Dominik Brodowski 2004-2006
Report errors and bugs to http://bugs.opensuse.org, please.
analyzing CPU 0:
driver: powernow-k8
CPUs which need to switch frequency at the same time: 0
hardware limits: 800 MHz - 2.80 GHz
available frequency steps: 2.80 GHz, 2.10 GHz, 1.60 GHz, 800 MHz
available cpufreq governors: conservative, userspace, powersave,
ondemand, performance
current policy: frequency should be within 800 MHz and 2.80 GHz.
The governor "performance" may decide
which speed to use
within this range.
current CPU frequency is 2.80 GHz (asserted by call to hardware).

(and similar for ...)
analyzing CPU 1:
analyzing CPU 2:
analyzing CPU 3:

and

cat /proc/cpuinfo
processor : 0
vendor_id : AuthenticAMD
cpu family : 16
model : 4
model name : AMD Phenom(tm) II X4 920 Processor
stepping : 2
cpu MHz : 2800.000
cache size : 512 KB
physical id : 0
siblings : 4
core id : 0
cpu cores : 4
apicid : 0
initial apicid : 0
fpu : yes
fpu_exception : yes
cpuid level : 5
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge
mca
cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt
pdpe1gb rdtscp lm 3dnowext 3dnow constant_tsc rep_good nopl pni
monitor cx16 popcnt lahf_lm cmp_legacy svm extapic cr8_legacy abm
sse4a misalignsse 3dnowprefetch osvw ibs skinit wdt
bogomips : 7448.31
TLB size : 1024 4K pages
clflush size : 64
cache_alignment : 64
address sizes : 48 bits physical, 48 bits virtual
power management: ts ttp tm stc 100mhzsteps hwpstate

(and similar for ...)
processor : 1
processor : 2
processor : 3


note that only 2.8GHz ('stock' CPU speed) is available as a cpufreq
option ... not trace of the ~ 3.7 GHz "actual" OC'd speed.

checking @ #irc, others (with other mobos, OS versions, configs, etc)
claim that BIOS clock speed == cpufreq-reported clock speed.

any pointers are appreciated!

thanks.
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