[LinuxPPS] Re: Something Funny going on with linuxPPS.

[clemens at dwf.com]

> On Wed, Oct 17, 2007 at 02:56:13PM -0600, clemens at dwf.com wrote:
> > OK, First the version.
> > I appear to be running the ntp-pps-2.6.23-rc2.diff with linux-2.6.22 and
> > the patch-2.6.23-rc6 .
> > 
> > So Im running the LinuxPPS rc2 patch with rc6.
> > 
> > With a test program that just prints out the time hacks (if they have changed)
> 
> As test program you mean "ppstest"?
> 
> > I see:
> > 
> > reg> [root at deneb Testing]# pps*4
> > fd2 = 3
> > getcap says 0x1133
> > getparam is 0x1113
> > set mode to 0x1113
> > getparam is 0x1113
> > Enter loop
> > 
> > A: 1192653829.3294954939 #437782
> >                            C: 1192653828.198436560 #437781
> > A: 1192653830.3294955022 #437783
> >                            C: 1192653829.198489907 #437782
> > A: 1192653831.3294955257 #437784
> >                            C: 1192653830.198540585 #437783
> > A: 1192653832.3294954727 #437785
> >                            C: 1192653831.198591520 #437784
> > A: 1192653833.3294955284 #437786
> >                            C: 1192653832.198644426 #437785
> > A: 1192653834.3294954791 #437787
> >                            C: 1192653833.198695348 #437786
> > A: 1192653835.3294955233 #437788
> >                            C: 1192653834.198746540 #437787
> > 
> > Note that the Assert for second 829.3 is followed by the Clear for second 
> > 828.19
> > This cant happen.
> > These time hacks MUST be in ascending order !!!
> > 
> > Somehow the Clear timehacks seem to be 2sec behind where they should be
> > relative to the Assert timehacks.
> > 
> > I apologize for not having had time to actually LOOK at the code, but 
> > Im officially retired now and should have more time for things like this.
> > Just once I get the stacks piled up on my desk cleared off...
> 
> I don't understand what you mean. In your log I see that both assert
> and clear events _are_ in ascending order. Of course you must consider
> them separately... :)
> 
But they must be interleaved !
The printout of assert and clear times must be monotonic,- the timestamps
must be increasing in time.
There is no way that a Clear event for 28.1 seconds can occur between the Assert
events at 29.3 seconds and 30.3 seconds.
The timestamp that SHOULD be there is for 30.1s  
Somehow, the 'second' part of it is 2seconds off 
   (or of course it could be the other way around) 

The very first time thru the loop one could have both assert and clear timestamps
waiting to print, and I guess they could be in the 'wrong' order, but after that, we 
get exactly one of Assert or Clear on a pass thru the loop and they MUST be 
time ordered.

Agreed?

-- 
                                        Reg.Clemens
                                        reg at dwf.com