svn commit: r334817 - in head/usr.sbin/cron: cron crontab lib

[Piotr P. Stefaniak]

On 2018-06-07 22:38:40, Gleb Smirnoff wrote:
>Author: glebius
>Date: Thu Jun  7 22:38:40 2018
>New Revision: 334817
>URL: https://svnweb.freebsd.org/changeset/base/334817
>
>Log:
>  Add new functionality and syntax to cron(1) to allow to run jobs at a
>  given interval, which is counted in seconds since exit of the previous
>  invocation of the job. Example user crontab entry:
>
>  @25	sleep 10
>
>  The example will launch 'sleep 10' every 35 seconds. This is a rather
>  useless example above, but clearly explains the functionality.
>
>  The practical goal here is to avoid overlap of previous job invocation
>  to a new one, or to avoid too short interval(s) for jobs that last long
>  and doesn't have any point of immediate launch soon after previous run.
>
>  Another useful effect of interval jobs can be noticed when a cluster of
>  machines periodically communicates with a single node. Running the task
>  time based creates too much load on the node. Running interval based
>  spreads invocations across machines in cluster. Note that -j/-J won't
>  help in this case.
>
>  Sponsored by:	Netflix

Missing a Relnotes tag, possibly.