On Tue, Sep 19, 2017 at 07:59:11PM -0600, levipear...@gmail.com wrote: > If some endpoint device shows up with direct Qbv support, this interface would > probably work well there too, although a talker would need to be able to > schedule its transmits pretty precisely to achieve the lowest possible > latency.
This is an argument for SO_TXTIME. > One concern here is calling the base-time parameter an interval; it's really > an absolute time with respect to the PTP timescale. Good documentation will > be important to this one, since the specification discusses some subtleties > regarding the impact of different time values chosen here. > > The format for specifying the actual intervals such as cycle-time could prove > to be an important detail as well; Qbv specifies cycle-time as a ratio of two > integers expressed in seconds, while extension-time is specified as an integer > number of nanoseconds. > > Precision with the cycle-time is especially important, since base-time can be > almost arbitrarily far in the past or future, and any given cycle start should > be calculable from the base-time plus/minus some integer multiple of cycle- > time. The above three points also. Thanks, Richard
