> I might do it one day, but so far I haven't had a really compelling reason to > do so. Probably using the Linux system clock (and phc2sys) will be good > enough > most of the time. It would be interesting to find out whether that is true > for your own application.
Richard, Think about this "simple" but very interesting problem. System time is not monotonic (assuming it is in UTC), PTP time yes (assuming it is TAI). In a real time control system you could have the need to make a "wait_until" or to execute some functions in a very well-defined time in spite of any clock adjustment made to recover some UTC leap second event. This could be a valid reason to implement these features on a PHC? William -----Original Message----- From: Richard Cochran [mailto:richardcoch...@gmail.com] Sent: 19 February 2014 15:41 To: Koehrer Mathias (ETAS/ESW5) Cc: linuxptp-users@lists.sourceforge.net Subject: Re: [Linuxptp-users] clock_nanosleep on /dev/ptpX On Wed, Feb 19, 2014 at 02:19:41PM +0000, Koehrer Mathias (ETAS/ESW5) wrote: > I want to run an application on each of the PCs, the execution should be > synchronized. Do you have specific performance requirements? > Does this mean that I have to use phc2sys to use the system clock again? Yes. > Or is there any way to work directly on the PTP clock? No. The dynamic posix clock implementation does allow the (future) possibility of implementing timers directly on the PHC devices. It would mean a fair amount of kernel work to actually make this work. > I might do it one day, but so far I haven't had a really compelling reason to > do so. Probably using the Linux system clock (and phc2sys) will be good > enough > most of the time. It would be interesting to find out whether that is true > for your own application. 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-users mailing list Linuxptp-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linuxptp-users ------------------------------------------------------------------------------ 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-users mailing list Linuxptp-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linuxptp-users
