[ntp:questions] Failed to test leapsecond's handling

Marco Marongiu brontolinux at gmail.com
Thu Mar 8 14:58:55 UTC 2012

Hi Miroslav, all

It looks like it took more than 15 seconds for this to work correctly...

Il 08/03/2012 14:28, Miroslav Lichvar ha scritto:
> Do you see the leap bit enabled in ntptime or adjtimex output?

I didn't check ntptime or adjtimex before, so I tried now: I re-set the
time to June 30th, 23:55:00 and I see the leap second armed in ntpq's rv:

associd=0 status=4519 leap_add_sec, sync_local, 1 event, leap_armed,

I didn't see the leap second armed immediately with adjtimex (adjtimex
--print | grep status returned 1 for a while), but now after a few
minutes it reports 17 correctly:

root at leapstick:~# adjtimex --print | grep status
       status: 17

while ntptime reports

root at leapstick:~# ntptime
ntp_gettime() returns code 1 (INS)
  time d39a1169.5d1d2000  Sat, Jun 30 2012 23:59:37.363, (.363726),
  maximum error 458280 us, estimated error 0 us
ntp_adjtime() returns code 1 (INS)
  modes 0x0 (),
  offset 0.000 us, frequency 97.395 ppm, interval 1 s,
  maximum error 458280 us, estimated error 0 us,
  status 0x11 (PLL,INS),
  time constant 6, precision 1.000 us, tolerance 500 ppm,

At the right time ntpd actually inserted the leap second:

Jun 30 23:59:59 leapstick kernel: [1293608.501308] Clock: inserting leap
second 23:59:60 UTC

And I verified that Squeeze actually steps back the clock :(

2012/06/30 23:59:59.999590790	0.000000008200004
2012/06/30 23:59:59.000300870	-0.000011565854948
2012/06/30 23:59:59.000996706	0.000000008054485

(the second column is the increment relative to the previous line)

For the record, this is uname -a on squeeze:

Linux leapstick 2.6.32-5-amd64 #1 SMP Mon Jan 16 16:22:28 UTC 2012
x86_64 GNU/Linux

I don't know if leap seconds are handled better in more recent kernels.

> Is the local timezone UTC?

It is.

> It would be interesting to also try "disable kernel" in the
> ntp.conf.

I can do that, if it's still some value. Please let me know.

Thanks for your help.

-- bronto

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