Create a loop of 1000ms at the exact second

gepebril69 has asked for the wisdom of the Perl Monks concerning the following question:

Hi there

Create a loop every second at hh:mm:ss.000000

For netwerkmonitoring I want to create a loop of 1 second and do a ping to another server

The result of this ping, with timeout set to 10000msec I want to store in a logfile. This logfile (ping-test_yyyymmdd.log will so be filled with yyyy-mm-dd hh:mm:ss;<response in ms> entries

- To do a ping with timeout of 10000ms -> No problem
- Store in logfile -> No problem
- Change the logfile very day -> No problem
- Fork a child, as some pings can time out and you don't want to influence the next ping -> No problem

Create a loop every 1000ms at the exact second, that I don't understand. So after 12:00:00 localtime start an event (fork child) at
hh:mm:ss:ms
12:00:00.000
12:00:01.000
12:00:02.000
12:00:03.000
etc, etc

Any clue on how to handle that issue?

Thanks in advance

Comment on Create a loop of 1000ms at the exact second

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Re: Create a loop of 1000ms at the exact second by RichardK (Parson) on Feb 20, 2015 at 11:14 UTC
That will depend on how you define 'exact', but on normal operating systems it's not possible to be all that precise. The help from Time::HiRes says this :- `Remember that unless you are working on a hard realtime system, any cl +ocks and timers will be imprecise, especially so if you are working i +n a pre-emptive multiuser system. Understand the difference between w +allclock time and process time (in UNIX-like systems the sum of user +and system times). Any attempt to sleep for X seconds will most proba +bly end up sleeping more than that, but don't be surprised if you end + up sleeping slightly less.` [download]	[reply] [d/l]
Re^2: Create a loop of 1000ms at the exact second by gepebril69 (Scribe) on Feb 21, 2015 at 15:04 UTC
Thanks Created a test script and all statements are true, unfortunately Have found a suitable workaround	[reply]
Re^3: Create a loop of 1000ms at the exact second by sundialsvc4 (Abbot) on Feb 23, 2015 at 01:38 UTC
Have found a suitable workaround. Which was what, exactly?
Re: Create a loop of 1000ms at the exact second by Discipulus (Canon) on Feb 20, 2015 at 10:27 UTC
Hello gepebril69, you can look at Time::Hires, if i understand your needs. Anyway 'exactly' is big word: i'll be satisfied by a good approximation. HtH L* There are no rules, there are no thumbs.. Reinvent the wheel, then learn The Wheel; may be one day you reinvent one of THE WHEELS.	[reply] [d/l]
Re^2: Create a loop of 1000ms at the exact second by gepebril69 (Scribe) on Feb 20, 2015 at 16:21 UTC
Thanks for the help	[reply]
Re^3: Create a loop of 1000ms at the exact second by sam_bakki (Pilgrim) on Feb 22, 2015 at 14:55 UTC
Hi If you really really want an exact timings, Try Raspberry PI with some RTOS, Like https://github.com/jameswalmsley/RaspberryPi-FreeRTOS. Thanks & Regards, Bakkiaraj M My Perl Gtk2 technology demo project - http://code.google.com/p/saaral-soft-search-spider/ , contributions are welcome.	[reply] [d/l]


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