sleep exactly after n seconds (sleep finishing longer than specified)
Hi, I have a script that forks a child. at the parent, i have a line that tells it to sleep for n seconds. Once the 3 seconds have passed, it will kill the child process. I noticed that most of the time, sleep doesn't count exact seconds.. most of the time it's longer. Is there any way to sleep precisely for n seconds? -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: sleep exactly after n seconds (sleep finishing longer than specified)
On Wed, Apr 22, 2009 at 09:27, Michael Alipio daem0n...@yahoo.com wrote: Hi, I have a script that forks a child. at the parent, i have a line that tells it to sleep for n seconds. Once the 3 seconds have passed, it will kill the child process. I noticed that most of the time, sleep doesn't count exact seconds.. most of the time it's longer. Is there any way to sleep precisely for n seconds? snip Not unless you are using a realtime OS. Your process might not get CPU time for n+m seconds. Until your process gets CPU time it doesn't matter what you put in sleep, nothing will happen. You may be able to schedule a process such that it will always have CPU time, but performance will suffer for everything else (which is why realtime OSes suck for everything but medical, weapon systems, and other tasks that must have sub-microsecond timing). You must trade speed for precision. -- Chas. Owens wonkden.net The most important skill a programmer can have is the ability to read. -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: sleep exactly after n seconds (sleep finishing longer than specified)
Michael Alipio wrote: Hi, Hello, I have a script that forks a child. at the parent, i have a line that tells it to sleep for n seconds. Once the 3 seconds have passed, it will kill the child process. I noticed that most of the time, sleep doesn't count exact seconds.. most of the time it's longer. Is there any way to sleep precisely for n seconds? Not really, but you can get finer grained timing using select() perldoc -f select Or the Time::HiRes module. perldoc Time::HiRes John -- Those people who think they know everything are a great annoyance to those of us who do.-- Isaac Asimov -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
