Date: Wed, 29 Dec 1999 20:01:25 +0200 From: Sheldon Hearn <sheldonh@uunet.co.za> To: Evren Yurtesen <yurtesen@dc.ispro.net> Cc: questions@FreeBSD.ORG Subject: Re: what is the difference between priority and nice levels Message-ID: <24089.946490485@axl.noc.iafrica.com> In-Reply-To: Your message of "Wed, 29 Dec 1999 19:53:10 %2B0200." <Pine.BSF.4.10.9912291947190.4336-100000@localhost>
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On Wed, 29 Dec 1999 19:53:10 +0200, Evren Yurtesen wrote: > What is the difference between priority and nice levels? Nice levels and priority are completely different things. Nice levels are a hint to the scheduler, indicating how frequently the process should be given a timeslice. Priority is an after-the-fact measurement. Basically, it's an indication of how frequently the scheduler had to stop the process because it used up its entire timeslice. Processes often don't use their entire timeslice because they sleep waiting for IO to complete. Processes that are more CPU-bound than IO-bound will tend to have higher priorities. The word ``priority'' in this context has nothing to do with its normal english meaning. It's just an indication of how CPU-bound a process is. > When I set the priority in login.conf why does it change the nice level? Ah, for that you'd have to look at the login.conf(5) manpage, which kinda hints at the fact that, in the context of the login.conf file, priority really means nice level. Horrible choice of words. :-) Hope this helps. Ciao, Sheldon. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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