Re: rdtsc to mili secs?

Pavel Machek
2000-11-15T21:34:22Z

Hi!

> > > Sensibly configured power saving/speed throttle systems do not change the
> > > frequency at all. The duty cycle is changed and this controls the cpu
> > > performance but the tsc is constant
> >
> > Do you have an example of notebook that does powersaving like that?
> > I have 2 examples of notebooks with changing TSC speed...
> >
>
> Intel PIIX-based systems will do duty-cycle throttling, for example.

Don't think so. My toshiba is PIIX-based, AFAIC:

root@bug:~# cat /proc/pci
Bus 0, device 5, function 0:
Bridge: Intel Corporation 82371AB PIIX4 ISA (rev 2).
Bus 0, device 5, function 1:
IDE interface: Intel Corporation 82371AB PIIX4 IDE (rev 1).
Master Capable. Latency=64.
I/O at 0x1000 [0x100f].
Bus 0, device 5, function 2:
USB Controller: Intel Corporation 82371AB PIIX4 USB (rev 1).
IRQ 11.
Master Capable. Latency=64.
I/O at 0xffe0 [0xffff].
Bus 0, device 5, function 3:
Bridge: Intel Corporation 82371AB PIIX4 ACPI (rev 2).

Still, it is willing to run with RDTSC at 300MHz, 150MHz, and
40MHz. (The last one in _extreme_ cases when CPU fan fails -- running
at 40MHz is better than cooking cpu).

--
I'm pavel@ucw.cz. "In my country we have almost anarchy and I don't care."
Panos Katsaloulis describing me w.r.t. patents at discuss@linmodems.org