CVS commit: src/sys

["Andrew Doran" <ad%netbsd.org@localhost>]

Module Name:    src
Committed By:   ad
Date:           Tue Dec  3 22:28:41 UTC 2019

Modified Files:
        src/sys/kern: kern_cpu.c kern_runq.c
        src/sys/sys: cpu_data.h sched.h

Log Message:
- Add some more failsafes to the CPU topology stuff, and build a 3rd
  circular list of peer CPUs in other packages, so we might scroll through
  them in the scheduler when looking to distribute or steal jobs.

- Fold the run queue data structure into spc_schedstate.  Makes kern_runq.c
  a far more pleasant place to work.

- Remove the code in sched_nextlwp() that tries to steal jobs from other
  CPUs.  It's not needed, because we do the very same thing in the idle LWP
  anyway.  Outside the VM system this was one of the the main causes of L3
  cache misses I saw during builds.  On my machine, this change yields a
  60%-70% drop in time on the "hackbench" benchmark (there's clearly a bit
  more going on here, but basically being less aggressive helps).


To generate a diff of this commit:
cvs rdiff -u -r1.79 -r1.80 src/sys/kern/kern_cpu.c
cvs rdiff -u -r1.52 -r1.53 src/sys/kern/kern_runq.c
cvs rdiff -u -r1.42 -r1.43 src/sys/sys/cpu_data.h
cvs rdiff -u -r1.78 -r1.79 src/sys/sys/sched.h

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.