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Tonglebeak
Guru
Joined: 23 Mar 2006
Posts: 362
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 Posted: Sat Feb 23, 2008 10:28 pm Post subject: CPU Frequency scaling problem |
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I have a 3200+ athlon64. The stock clock speed is 2.0ghz, but I've had it oc'd to 2.4 ever since I got it...
Today, I compiled in cpu scaling. For whatever reason, cpufreq is only detecting the stock clock speed, and setting it as the max, rather than detecting my overclock speed. So now my cpu will onlyi run 2ghz max instead of 2.4ghz (yes, it's still overclocked in bios).
Anyway to force cpufreq to use 2.4ghz as the max? |
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d2_racing
Bodhisattva
Joined: 25 Apr 2005
Posts: 13047
Location: Ste-Foy,Canada
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| Posted: Sun Feb 24, 2008 1:53 am Post subject: |
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Maybe CPUFREQ use the spec that are from /proc/cpuinfo.
I think that there is a way do overright your cpu speed manually. |
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Yak
Tux's lil' helper
Joined: 01 Sep 2002
Posts: 107
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| Posted: Sun Feb 24, 2008 2:07 am Post subject: |
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| Have a look at the files in /sys/devices/system/cpu/cpu0/cpufreq/ if you haven't already. It should show the min, max, current, and available frequencies, and current and available governors. I've not had much luck with scaling an overclocked athlon64 so far, though. |
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joaopft
Tux's lil' helper
Joined: 20 Oct 2003
Posts: 86
Location: Lisbon, Portugal
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| Posted: Mon Mar 31, 2008 11:07 pm Post subject: |
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With cpufreq compiled in the kernel and an overclocked/underclocked processor, the processor clockspeed reported in /proc/cpuinfo is but a nominal value. This particular /proc/cpuinfo line gets used by userspace apps like Ksensors, etc, and is is very annoying having these apps report fictional clockspeed values...
For kernel 2.6.24 (64 bits) patch the kernel with the following to solve the issue:
| Code: |
--- linux/arch/x86/kernel/setup_64.c.old 2008-03-24 15:07:26.000000000 +0000
+++ linux/arch/x86/kernel/setup_64.c 2008-03-24 15:04:05.000000000 +0000
@@ -1098,8 +1098,12 @@
if (cpu_has(c,X86_FEATURE_TSC)) {
unsigned int freq = cpufreq_quick_get((unsigned)cpu);
+ static unsigned int nominal_max;
+ nominal_max = freq > nominal_max ? freq : nominal_max;
if (!freq)
freq = cpu_khz;
+ else
+ freq = (unsigned int) (freq * (1.0*cpu_khz)/nominal_max);
seq_printf(m, "cpu MHz\t\t: %u.%03u\n",
freq / 1000, (freq % 1000));
}
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To patch: make sure /usr/src/linux points to a 2.6.24 kernel;
create file /usr/src/cpufreqpatch-2.6.24 with the above code;
run
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cd /usr/src
patch -p0 <cpufreqpatch-2.6.24 |
Now, recompile the kernel.
Notes: 1. This patch has no effect on a 32 bit kernel.
2. The patched kernel was (successfully) tested on two Athlon 64 systems.
3. I can't promise the patched kernel won't break your system.
_________________
Fiction is obliged to stick to possibilities. Truth isn't.
Mark Twain |
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