[LinuxPPS] Something that needs to be fixed (unnormalized times)

clemens at dwf.com clemens at dwf.com
Sun Oct 21 07:20:37 CEST 2007


Im not sure if this is the ultimate cause of the problems Im seeing, 
Ill walk thru the code and do the arithmetic tomorrow, but LinuxPPS
is not normalizing the timestamps it returns to the user.
Here are some results from looking at /sys/class/pps/pps1:

more assert ; more clear
1192942684.-1000065670#130025
1192942683.198143070#130025
[reg at deneb pps1]$ !!
more assert ; more clear
1192942685.-1000064840#130026
1192942684.198196162#130026
[reg at deneb pps1]$ !!
more assert ; more clear
1192942686.-1000065410#130027
1192942685.198262433#130027
[reg at deneb pps1]$ !!
more assert ; more clear
1192942687.-1000063955#130028
1192942686.198294543#130028

Here is what my ppsapitest (similar to Rodolfo's ppstest) sees
when it prints the two halves of the timestamp as integers

A: 1192942683.3294902895 #130024     C: 1192942681.199043229 #130023
A: 1192942683.3294902895 #130024     C: 1192942682.198092421 #130024
A: 1192942684.3294901626 #130025     C: 1192942682.198092421 #130024
A: 1192942684.3294901626 #130025     C: 1192942683.198143070 #130025
A: 1192942685.3294902456 #130026     C: 1192942683.198143070 #130025
A: 1192942685.3294902456 #130026     C: 1192942684.198196162 #130026
A: 1192942686.3294901886 #130027     C: 1192942684.198196162 #130026
A: 1192942686.3294901886 #130027     C: 1192942685.198262433 #130027
A: 1192942687.3294903341 #130028     C: 1192942685.198262433 #130027
A: 1192942687.3294903341 #130028     C: 1192942686.198294543 #130028
A: 1192942688.3294902715 #130029     C: 1192942686.198294543 #130028

The numbers with positive ns are fine, but those with -(1+eps) ns are
being printed incorrectly.  Im guessing that there is some normalization
going on, but it isnt working for the -1 sec ...  Ill run that down tomorrow,
but thought Id post this tonight.

-- 
                                        Reg.Clemens
                                        reg at dwf.com





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