Re: Nice 19 process still gets some CPU

[Con Kolivas <kernel@kolivas.org>]

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Michael Buesch wrote:
| Quoting Chris Friesen <cfriesen@nortelnetworks.com>:
|
|>>Timothy Miller wrote:
|>>
|>>>
|>>>Con Kolivas wrote:
|>>>
|>>> >
|>>> > It definitely should _not_ starve. That is the unixy way of doing
|>>> > things. Everything must go forward. Around 5% cpu for nice 19 sounds
|>>> > just right. If you want scheduling only when there's spare cpu cycles
|>>> > you need a sched batch(idle) implementation.
|>>> >
|>>> >
|>>>
|>>>Well, since I can't rewrite the app, I can't make it sched batch.  Nice
|>>>values are an easy thing to get at for anything that's running.
|>>
|>>Sure you can.  You can set the scheduler policy on any process in the
system,
|>>while its running.
|>>
|>>int sched_setscheduler(pid_t pid, int policy, const struct
sched_param *p);
|>>
|>>Takes about two minutes to write an equivalent to "nice" to set
scheduler
|>>policies and priorities.
|
|
| Sounds cool. I was searching this syscall for a long time, now. :)
| But batch scheduling is available in -ck only, so this works only
| with -ck kernels. Correct?

Easy to do with the wrapper too:
schedtool -B $pid

or if it's not running yet:
schedtool -B -e $application

schedtool is here:
http://freshmeat.net/projects/schedtool/?topic_id=136

Con
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