Messages in this thread | | | Date | Thu, 14 Oct 2010 18:50:02 +0900 | From | KAMEZAWA Hiroyuki <> | Subject | Re: [PATCH v3 3/7] sched: throttle cfs_rq entities which exceed their local quota |
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On Thu, 14 Oct 2010 11:12:22 +0200 Peter Zijlstra <peterz@infradead.org> wrote:
> On Wed, 2010-10-13 at 15:34 +0900, KAMEZAWA Hiroyuki wrote: > > cpu.share and bandwidth control can't be used simultaneously or... > > is this fair ? I'm not familiar with scheduler but this allows boost this tg. > > Could you add a brief documentaion of a spec/feature. in the next post ? > > Like explained, shares control the proportional distribution of time > between groups, bandwidth puts a limit on how much time a group can > take. It can cause a group to receive less than its fair share, but > never more. > > There is, however, a problem with all this, and that is that all this > explicit idling of tasks can lead to a form of priority inversion. > Regular preemptive scheduling already suffers from this, but explicitly > idling tasks exacerbates the situation. > > You basically get to add the longest induced idle time to all your lock > hold times. >
What is the user-visible difference of the problem between 1) limit share to be very small. 2) use throttole.
If share is used, lock-hodler's priority is boosted ?
Thanks, -Kame
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