Messages in this thread | | | Date | Thu, 03 Feb 2005 14:25:43 +1100 | From | Peter Williams <> | Subject | Re: [patch, 2.6.11-rc2] sched: RLIMIT_RT_CPU_RATIO feature |
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Bill Huey (hui) wrote: > On Thu, Feb 03, 2005 at 08:54:24AM +1100, Peter Williams wrote: > >>As Ingo said in an earlier a post, with a little ingenuity this problem >>can be solved in user space. The programs in question can be setuid >>root so that they can set RT scheduling policy BUT have their >>permissions set so that they only executable by owner and group with the >>group set to a group that only contains those users that have permission >>to run this program in RT mode. If you wish to allow other users to run >>the program but not in RT mode then you would need two copies of the >>program: one set up as above and the other with normal permissions. > > > Again, in my post that you snipped you didn't either read or understand > what I was saying regarding QoS,
I guess that I thought that it was overkill for the problem under discussion and probably won't solve it anyway. Giving any task special preferential (emphasis on the preferential) treatment should require authorization by a suitably privileged entity at some stage. So the problem of how ordinary users manage to launch tasks that receive preferential treatment will remain.
> nor about the large scale issues regarding > dual/single kernel development environments. Ultimately this stuff requires > non-trivial support in kernel space, a softirq thread migration mechanism > and a frame driven scheduler to back IO submission across async boundaries. > > My posts where pretty clear on this topic and lot of this has origins > coming from SGI IRIX. Yes, SGI IRIX. One of the only system man enough > to handle this stuff. > > Ancient, antiquated Unix scheduler semantics (sort and run) and lack of > control over critical facilities like softirq processing are obstacles > to getting at this.
Sorry for upsetting you, Peter -- Peter Williams pwil3058@bigpond.net.au
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