A realtime preemption overview
Posted Aug 15, 2005 9:26 UTC (Mon) by balbir
Parent article: A realtime preemption overview
Wow! Paul amazingly good article. I hope you write a book on the Linux kernel and RCU someday, your pedagogy style is very good.
I have so many comments (mostly doubts), I will probably start a few at a time.
It has been mentioned that
1. Interrupt handlers being pre-emptible and now run in process context
I remember that BSD based implementation of X86 have always used an SPL() level to keep interrupt handlers pre-emptive based on priority, couldn't we adopt this approach. With interrupts being handled in process context, I see a scheduling overhead for each interrupt being executed, what does this do to interrupt latency?
2. With spin-locks now being able to block, would it be a good idea to create an alias (with a different name) to spinlock, since a spinlock might no longer spin as its name suggests (I hope I understood this correctly)
3. I like that priority inheritence is now being implemented in the linux kernel.
4. There seems to be an inbuilt assumption that the lesser we run in interrupt context and the more in process context, the better. I agree with this principle, but there might be exceptions (for example point 1, above).
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