[Suzaku-en:00581] Re: Suzaku SZ030 time leaps

Florian Painke email@hidden
Thu Apr 24 18:30:29 JST 2008


Hi!

>> I've just recently installed ntpclient on my Suzaku SZ030 uClinux. 
>> During the procedure to measure the error in frequency as described in 
>> the ntpclient HOWTO I came across something strange.
>> There are rather large sudden time leaps of several seconds. I.e. when 
>> measuring the deviation in respect to the ntp server, first it would be 
>> somewhat steady, say, a few milliseconds each minute. Then, from one 
>> point measuring to the next, there's a leap of a few seconds. Largest 
>> I've experienced so far is 150 seconds! From there on deviation will be 
>> steady again, alas the offset from the time leap stays, of course.

> 150sec is way long.  how often do you see that jump?
> let us know if you have any further info.

Well, I'm trying to track down the problem right now. It seems it has to 
do with changing the system date/time, not necessarily only when using 
ntpclient. And it seems to be connected to one of the daemons running, I 
just haven't been able to figure out, which one it is.
I added a script to the boot process that waits for a dhcp lease and 
synchronizes to a local ntp server. I used to do this last in the boot 
process. Then about five to seven minutes later, the first "time leap" 
would occur.
It's actually not a "leap" - the board just hangs for about two to four 
minutes and then continues. The "time leap" is just the time the board 
hangs.
When I leave out the ntp script, hangs won't occur until i call ntp or 
change the date manually. Then, again after five to seven minutes, the 
system hangs, and thus "leaps".

As of now, I seem to have found a way around the problem. I now use the 
ntp boot script right after the network script, i.e. I added 
S45ntpclient to  /etc/rc.d. So adjusting the system date/time comes 
before starting the remaining daemons. It seems the hangs and leaps have 
gone away, so far.
It's not completely satisfying, since I still don't know, what exactly 
causes the system to hang.

Regards, Florian.



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