Messages in this thread | | | Date | Wed, 9 Feb 2000 11:21:38 -0500 (EST) | From | John Regehr <> | Subject | Re: latest 'guaranteed low latency' patch against 2.2.14 |
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> how do you improve task-execution latency without rescheduling actually? > Short of adding new hardware, or without adding a new (limited) API to > execute user-specified code. Ie. how do you reschedule to a generic > user-task without actually rescheduling?
Well, in NT, IRIX, BeOS, and (I think) Solaris tasks running in kernel mode can be preempted any time as long as they're not holding a spinlock.
Certainly making a kernel preemptible increases complexity. I'd be interested in hearing about the tradeoffs here - hasn't Larry McVoy talked about this in the past on this list?
> any device interrupt can be turned into an NMI interrupt - of course > special handlers have to be written, and careful coding is needed as no > other kernel facilities can be relied on.
Won't this hose RT-Linux? If random device drivers start using NMI (as Alan Cox suggested in a different mail) then it would be really nice if there was a way to disable this behavior at compile time.
John Regehr
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