Problem with clock setting

Joel Sherrill joel.sherrill at
Fri Jan 19 17:17:09 UTC 2007

Lars Törnkvist wrote:
> Hi,
> Recently we started using the clock manager. When we set the clock forward in time a peculiar thing happen, the system will "freeze" for a while and then start working again. The time it freezes is direct linear to the amount of time we step forward, for each hour there will be about 30 seconds of "freezing". Since the clock is correct after the "freeze" period (the 30 secs hasn't disappeared) RTEMS obviously doesn't freeze, the system just becomes unresponsive. 
> Is this the way its supposed to be or have we done something wrong or forgotten something? Is there a way to avoid this "freeze" thing?
When the clock is adjusted forward, any events scheduled to fire must be 
processed.  If there were no
events on the Seconds watchdog chain, then it should take 0 time to 
execute.  The list of scheduled
activities is adjusted forward in chunks based upon how long each 
pending event has left.

I assume you have a lot of time based events which are triggered by the 
time change.  Check out the
source in cpukit/score/src/watchdogadjust.c. 

It looks like if there is an adjustment which empties the chain, the 
loop breaks. 

Please confirm if you do or don't have a lot of activities scheduled 
based upon wall-time. 
> We are running RTEMS 4.6.6 on a Coldfire system and it works fine otherwise.
> Thankful for any help on this.
> Regards
> Lars Törnkvist
> Solid Software AB
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