On Tue, Feb 18, 2014 at 06:29:11PM +0100, Holzinger, Axel (ALC NetworX GmbH) wrote> > what is the motivation between the different cases (tuning the clock and not > tuning the clock in PTP/gPTP). Is this demanded by the standard or good > practice?
IEEE 1588 does not tell you how to adjust slave clocks, and gPTP says *not* to adjust the slave clock. The gPTP people are worried about "gain peaks" that occur (if I understood correctly) when adjusting a chain of clocks all at the same time. There are some reports of simulation results floating around the web that show poor synchronization in this particular case. > How does another process read the network (PTP) time if the PHC doesn't > reflect it, because it's free running. The process must calculate the network time from the offsets. In gPTP there is a really awful API specified for this, but we offer the TIME_STATUS_NP management message instead. Thanks, Richard ------------------------------------------------------------------------------ Managing the Performance of Cloud-Based Applications Take advantage of what the Cloud has to offer - Avoid Common Pitfalls. Read the Whitepaper. http://pubads.g.doubleclick.net/gampad/clk?id=121054471&iu=/4140/ostg.clktrk _______________________________________________ Linuxptp-devel mailing list Linuxptp-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linuxptp-devel
