Messages in this thread | | | Date | Mon, 24 Feb 2003 02:11:36 -0800 | Subject | Re: Minutes from Feb 21 LSE Call | From | Bill Huey (Hui) <> |
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On Mon, Feb 24, 2003 at 01:56:25AM -0800, Andrew Morton wrote: > But that is speculation as well - I never observed this aspect to be > a real problem. Probably, it was not. > > Substantiation of your claim requires quality testing and a plausible > explanation. I do not believe we have seen either, OK?
Well, let's back off here. It's not my claim, it's Robert Love's in that URL. Not to arrange a fight, but I had to point that out. :)
> > http://linuxdevices.com/articles/AT6106723802.html > > I did, briefly. It appears to be claiming that the average scheduling > latency of the non-preemptible kernel is ten milliseconds!
They mention that this is related to the console code. Obviously, if you're not checking for reschedule in a big pix map scroll blit, then it's going to stick out boldly as a big latency spike.
A fully preemptive system would only turn off preemption in places that would break drivers and other obvious places like scheduler run-queues, etc...
> Maybe I need to read that again in the morning.
It's also an old article, but goes over a lot of the basics of a fully preemptable kernel like that. Things might not be as dramatic now with 2.5.62. Not sure how things are now...
bill
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