Messages in this thread | | | Date | Mon, 14 Jan 2002 19:07:46 -0800 | From | george anzinger <> | Subject | Re: [2.4.17/18pre] VM and swap - it's really unusable |
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Daniel Phillips wrote: > > On January 14, 2002 10:09 am, yodaiken@fsmlabs.com wrote: > > UNIX generally tries to ensure liveness. So you know that > > cat lkarchive | grep feel | wc > > will complete and not just that, it will run pretty reasonably because > > for UNIX _every_ process is important and gets cpu and IO time. > > When you start trying to add special low latency tasks, you endanger > > liveness. And preempt is especially corrosive because one of the > > mechanisms UNIX uses to assure liveness is to make sure that once a > > process starts it can do a significant chunk of work. > If I read this right, your complaint is not with preemption but with scheduler policy. Clearly both are needed to "assure liveness". Another way of looking at preemption is that is enables a more responsive and nimble scheduler policy (afterall it is the scheduler that decided that task A should give way to task B. All preemption does is to allow that to happen with greater dispatch.) Given that, we can then discuss what scheduler policy should be. -- George george@mvista.com High-res-timers: http://sourceforge.net/projects/high-res-timers/ Real time sched: http://sourceforge.net/projects/rtsched/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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