Re: Idle priority
Re: Idle priority
- Subject: Re: Idle priority
- From: Michael Smith <email@hidden>
- Date: Wed, 29 Jul 2009 21:41:26 -0700
On Jul 29, 2009, at 9:24 PM, William Kucharski wrote: Terry Lambert wrote: How about you guys describe what you are trying to do?
I can't speak for the others, but I suspect what they're trying to do is the equivalent of "nice -19" on other UNIXes, which means "run this task only if there are no tasks other than idle to run."
Or this task should only be run if the system has absolutely NOTHING else (other than other tasks of the same priority) to do.
That's what the minimum regular priority is for. The system reserves the right to decide that something else is even less important.
You're making the usual mistake of thinking that your process is somehow special, although in this case that it's somehow less important than other unimportant things. Mark it as not interesting, then let the system decide what to do about it. Think things like SETI@Home
SETI@Home is incompatible with any sort of power management, unless it is willing to intentionally constrain its duty cycle. Making it an "idle" process is lying to everyone about what it's really doing. or perhaps a screensaver.
"Screensavers" serve two purposes; saving power (in which case they turn the display off and then consume zero cycles, so they are not interesting here) and looking pretty.
You can't get enough work done reliably at "idle" priority to look pretty, and so most modern "screen savers" actually need to run at a fairly elevated priority to meet their realtime deadlines.
= Mike
-- Ars longa, vita brevis, occasio praeceps, experimentum periculosum, iudicium difficile -- Hippocrates
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