Messages in this thread | | | Date | Fri, 2 Aug 2002 05:57:01 +0200 | From | Nico Schottelius <> | Subject | Re: cpu speed is 165mhz instead of real 650mhz |
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Once again I am on a 147Mhz system....
george anzinger [Wed, Jul 24, 2002 at 01:13:18PM -0700]: > Nico Schottelius wrote: > > Joshua Uziel [Wed, Jul 24, 2002 at 03:27:09AM -0700]: > > > * Nico Schottelius <nicos-mutt@pcsystems.de> [020724 02:03]: > > > > 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. > > > The cpu speed is detected by comparing the TSC against the > PIT.
I don't even now any of these both.
> 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.
> 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.
Nice explanation. I think I understood 85 % of it :)
Nico
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