#
346513 |
|
22-Apr-2019 |
kevans |
MFC r334817, r334910
r334817: 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.
r334910: Remove old, dead compat code.
We no longer need to od these things conditionally, and the fallbacks are to 4.2BSD era defaults, which nobody uses anymore. Vixie cron has diverged from upstream anyway in our tree, and it's not clear there's actually a viable upstream anymore. Plus, we don't follow the vendor-supplied code pattern here.
I'm doing this to reduce false positives from grep.
|
#
21673 |
|
14-Jan-1997 |
jkh |
Make the long-awaited change from $Id$ to $FreeBSD$
This will make a number of things easier in the future, as well as (finally!) avoiding the Id-smashing problem which has plagued developers for so long.
Boy, I'm glad we're not using sup anymore. This update would have been insane otherwise.
|