cpu speed is 165mhz instead of real 650mhz
Hello guys!
This periodicly appears in my system. The Kernel seems to misdetect the right cpu speed and then it's running only at 165mhz.
I don't really understand why this happens, there's no acpi enabled, which caused this failure the last time.
I attached .config of 2.5.24 [which still runs fine with devfs :) ] and /proc/cpuinfo.
Please cc me when answering.
Nico
Signature · 3 lines
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Quoted 4 lines · Nico Schottelius
This periodicly appears in my system. The Kernel seems to misdetect the right cpu speed and then it's running only at 165mhz.
I don't really understand why this happens, there's no acpi enabled, which caused this failure the last time.
Is this a notebook computer? Is it that you're sometimes booting it up while the system is unplugged (ie. on battery)?
Joshua Uziel [Wed, Jul 24, 2002 at 03:27:09AM -0700]:
Quoted 8 lines · Nico Schottelius
Quoted 4 lines
This periodicly appears in my system. The Kernel seems to misdetect the right cpu speed and then it's running only at 165mhz.
I don't really understand why this happens, there's no acpi enabled, which caused this failure the last time.Is this a notebook computer? Is it that you're sometimes booting it up while the system is unplugged (ie. on battery)?
yes,it is, but slowing down to 500 mhz is the only available speedstep option.
165 or similar is not supported (afaik) by the bios/processor.
Nico
Signature · 3 lines
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Quoted 8 lines · Nico Schottelius
Joshua Uziel [Wed, Jul 24, 2002 at 03:27:09AM -0700]:
Quoted 6 lines · Nico Schottelius
Quoted 4 lines
This periodicly appears in my system. The Kernel seems to misdetect the right cpu speed and then it's running only at 165mhz.
I don't really understand why this happens, there's no acpi enabled, which caused this failure the last time.
Quoted 8 lines
Quoted 2 lines
Is this a notebook computer? Is it that you're sometimes booting it up while the system is unplugged (ie. on battery)?
yes,it is, but slowing down to 500 mhz is the only available speedstep option.
165 or similar is not supported (afaik) by the bios/processor.
The cpu speed is detected by comparing the TSC against the PIT. The PIT is used to drive the clock. If it is wrong by this much you should see time drifting like mad. If the TSC is wrong, you should see errors in the sub 1/HZ correction applied to get_time_of_day(). You could detect this by looping on a get_time_of_day() call and noticing that time slides ahead 3/HZ seconds and then back each tick. What would be happening is that the interpolation code would be taking the fast TSC (i.e. 500MHZ when it thought it was 165) and be pushing time out beyond the next tick value. Each tick this would reset and be replayed. If neither of these is happening, the reported value is most likely what is really going on.
Signature · 6 lines
George Anzinger [email protected] High-res-timers: http://sourceforge.net/projects/high-res-timers/ Real time sched: http://sourceforge.net/projects/rtsched/ Preemption patch: http://www.kernel.org/pub/linux/kernel/people/rml
Once again I am on a 147Mhz system....
george anzinger [Wed, Jul 24, 2002 at 01:13:18PM -0700]:
Quoted 11 lines
Quoted 10 lines · Nico Schottelius
Joshua Uziel [Wed, Jul 24, 2002 at 03:27:09AM -0700]:
Quoted 8 lines · Nico Schottelius
Quoted 4 lines
This periodicly appears in my system. The Kernel seems to misdetect the right cpu speed and then it's running only at 165mhz.
I don't really understand why this happens, there's no acpi enabled, which caused this failure the last time.Is this a notebook computer? Is it that you're sometimes booting it up while the system is unplugged (ie. on battery)?
Quoted 7 lines
Quoted 5 lines
yes,it is, but slowing down to 500 mhz is the only available speedstep option.
165 or similar is not supported (afaik) by the bios/processor.
The cpu speed is detected by comparing the TSC against the PIT.
I don't even now any of these both.
Quoted 2 lines
The PIT is used to drive the clock. If it is wrong by this much you should see time drifting like mad.
Hey, you are right! Instead of 13 o'clock it's 5 o'clock. What todo now ? I am staying on this downclocked system, if you need some more informations.
Quoted 4 lines
If the TSC
is wrong, you should see errors in the sub 1/HZ correction applied toget_time_of_day().
You could detect this by
Quoted 8 lines
looping on a
get_time_of_day()call and noticing that time slides ahead 3/HZ seconds and then back each tick. What would be happening is that the interpolation code would be taking the fast TSC (i.e. 500MHZ when it thought it was 165) and be pushing time out beyond the next tick value. Each tick this would reset and be replayed. If neither of these is happening, the reported value is most likely what is really going on.
Nice explanation. I think I understood 85 % of it :)
Nico
Signature · 5 lines
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