On Mon, Feb 12, 2018 at 02:39:06PM -0800, Jesus Sanchez-Palencia wrote: > On 01/18/2018 12:42 AM, Miroslav Lichvar wrote: > > Please keep in mind that the PHCs and the system clock don't have to > > be synchronized to each other. If I understand the rest of the series > > correctly, there is an assumption that the PHCs are keeping time in > > TAI and CLOCK_TAI can be used as a fallback. > > Just to double-check, imagine that I've configured the qdisc for > SW best-effort and with clockid CLOCK_REALTIME. When it receives a > packet with the clockid of a /dev/ptpX, the qdisc should just drop that > packet, right?
Yes, I think it should drop it. The kernel does not know the offset between the two clocks (they don't even have to be synchronized), so it cannot convert a PHC-based TX time to the system time. -- Miroslav Lichvar
