Re: [PATCH] RTC: Add mmap method to rtc character driver

Arjan van de Ven
2006-07-25T19:06:54Z

> > well the idea that has been tossed about a few times is using a vsyscall
> > function that either calls into the kernel, or directly uses the hpet
> > page (which can be user mapped) to get time information that way...
> > or even would use rdtsc in a way the kernel knows is safe (eg corrected
> > for the local cpu's speed and offset etc etc).
> >
> Ok, that makes sense, although thats only going to be supportable on hpet
> enabled systems right?

well it's only going to be *fast* on hpet enabled systems (which should
be the *vast* majority nowadays if it wasn't for some silly bios
defaults by some vendors); all others can just fall back to other
methods. The beauty of the vsyscall concept :)

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