Messages in this thread | | | Date | Tue, 2 Jun 2015 21:33:25 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: [PATCH RFC] x86, tsc: Allow for high latency in quick_pit_calibrate() |
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On Thu, 21 May 2015, Adrian Hunter wrote:
> If it takes longer than 12us to read the PIT counter lsb/msb, > then the error margin will never fall below 500ppm within 50ms, > and Fast TSC calibration will always fail.
So finally the legacy PIT emulation takes longer than the 30 years old hardware implementation. Progress!
> This patch detects when that will happen and switches to using > a slightly different algorithm that takes advantage of the PIT's > latch comand.
Is there really no smarter way to figure out the TSC frequency on modern systems?
Thanks,
tglx
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