[PATCH v6 0/8] ptp: IEEE 1588 hardware clock support

Christian Riesch christian at riesch.at
Fri Sep 24 07:34:06 EST 2010

Alan Cox wrote:
>> It implies clock tuning in userspace for a potential sub microsecond
>> accurate clock. The clock accuracy will be limited by user space
>> latencies and noise. You wont be able to discipline the system clock
>> accurately.
> Noise matters, latency doesn't. 

Well put! That's why we need hardware support for PTP timestamping to 
reduce the noise, but get along well with the clock servo that is 
steering the PHC in user space.


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