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- Remove the double queue mechanism for timeshare threads. It was slow due to excess cache lines in play, caused suboptimal scheduling behavior with niced and other non-interactive processes, complicated priority lending, etc. - Use a circular queue with a floating starting index for timeshare threads. Enforces fairness by moving the insertion point closer to threads with worse priorities over time. - Give interactive timeshare threads real-time user-space priorities and place them on the realtime/ithd queue. - Select non-interactive timeshare thread priorities based on their cpu utilization over the last 10 seconds combined with the nice value. This gives us more sane priorities and behavior in a loaded system as compared to the old method of using the interactivity score. The interactive score quickly hit a ceiling if threads were non-interactive and penalized new hog threads. - Use one slice size for all threads. The slice is not currently dynamically set to adjust scheduling behavior of different threads. - Add some new sysctls for scheduling parameters. Bug fixes/Clean up: - Fix zeroing of td_sched after initialization in sched_fork_thread() caused by recent ksegrp removal. - Fix KSE interactivity issues related to frequent forking and exiting of kse threads. We simply disable the penalty for thread creation and exit for kse threads. - Cleanup the cpu estimator by using tickincr here as well. Keep ticks and ltick/ftick in the same frequency. Previously ticks were stathz and others were hz. - Lots of new and updated comments. - Many many others. Tested on: up x86/amd64, 8way amd64.
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