[LinuxPPS] Timestamps with LinuxPPS

[Bernhard Schiffner]

Hallo John,

almost a year ago was a little discussion in LinuxPPS about making the 
/dev/pps* readable, returning a timestamp.
There was a patch (and still is) doing so but the thread stoped because of 
other priorities.
(IIRC I sent you some private e-mail on this topic.)

A recent discussion showed that users want to have a "normal" read() and 
something to use with select() in addition to the RFC2783 functionality.

http://ml.enneenne.com/pipermail/linuxpps/2010-March/003647.html

My question to you:
Do you know something how others (parts in the kernel, operating systems ...) 
handle these problems?
(Format of timestamps, mechanisms to trigger select()  etc.)

Examples: 
http://publib.boulder.ibm.com/infocenter/radhelp/v6r0m1/index.jsp?topic=/com.ibm.etools.egl.doc/topics/reglasm0901.html
doesn't mention the ns-part (only -S / ms).

man date reveals the +%N format for nanoseconds

The recent patch adds the slope triggering the timestamp and a counter for 
each slope:

       assert 577917 1236209879.010016955
        clear 577917 1236209879.011017749

About a Plan9 inspired /dev/time (IIR not mainline yet)
http://lwn.net/Articles/323658/

Every hint / link / suggestion from your side is welcomed.

TIA!


Bernhard