[ntp:hackers] Serial port jitter in FreeBSD

John Pettitt jpp at cloudview.com
Wed Oct 26 09:55:44 PDT 2005



David L. Mills wrote:

> Guys,
>
> The serial port jitter with refclocks and FreeBSD rackety and mort is
> rather huge. I have a vague recollection of what can be done about
> that, specifically to diable the UART FIFO and software queue in the
> driver. I've done that for most of the systems here, but haven't a
> clue how to do that with FreeBSD and various motherboards. I've surfed
> www.freebsd.org with no joy. Help?
>
> Dave
>

hint.sio.X.flags with the 0x0002 bit set  in /boot/device.hints will
disable the FIFO- "man sio" for more info.

John


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