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SubjectRe: How is user space notified of CPU speed changes?
On Fri, 2004-10-22 at 13:40 -0600, Chris Friesen wrote:
> Lee Revell wrote:
> > Seems like you are implying that any userspace app that needs to know
> > the CPU speed is broken. Is this correct?
> No, we're saying that Intel's tsc implementation is broken. <grin>
> x86 really could use an on-die register that increments at 1GHz independent of
> clock speed and is synchronized across all CPUs in an SMP box.

Like this? (posted to jackit-devel):

On Fri, 2004-10-22 at 18:20 -0500, Jack O'Quin wrote:

> On PowerPC, JACK uses the lower half of the 64-bit Timebase register,
> which is accessible from user mode. This is better then the i386
> cycle counter, I believe. See: `config/cpu/powerpc/cycles.h', the
> comment about only using it for SMP is bogus. We use this for both
> MacOS X and Linux.

Lee Revell <>

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