Odd Time of Day Reported with Ticker

Sebastian Huber sebastian.huber at embedded-brains.de
Tue Jan 19 14:57:08 UTC 2016

On 19/01/16 15:39, Joel Sherrill wrote:
> The tasks are delaying 500, 1000, and 1500 ticks 
> with nanoseconds_per_tick = 10000000. Delay operations are guaranteed 
> to be a minimum of the requested amount and this is not being honored.

For the ticks based services this is not true, you wait to the n-th 
tick. If you are 1ps before it, you wait 1ps + interrupt processing time.

> I know this is a duration specified in clock ticks but it is really 
> (ticks * nanoseconds per tick) long in real time.
> I have not checked delays like sleep() and nanosleep() but tick based 
> ones are 1 tick too short.

This is a known issue and results for example in libstdc++ testsuite 

Sebastian Huber, embedded brains GmbH

Address : Dornierstr. 4, D-82178 Puchheim, Germany
Phone   : +49 89 189 47 41-16
Fax     : +49 89 189 47 41-09
E-Mail  : sebastian.huber at embedded-brains.de
PGP     : Public key available on request.

Diese Nachricht ist keine geschäftliche Mitteilung im Sinne des EHUG.

More information about the devel mailing list