cvs commit: src/sys/kern init_main.c kern_synch.c src/sys/sys globaldata.h param.h proc.h thread2.h

Matthew Dillon dillon at
Tue Nov 8 12:51:51 PST 2005

dillon      2005/11/08 12:47:02 PST

DragonFly src repository

  Modified files:
    sys/kern             init_main.c kern_synch.c 
    sys/sys              globaldata.h param.h proc.h thread2.h 
  Make tsleep/wakeup MP SAFE part 1/2.
  Make most of the tsleep/wakeup core code MP safe.   Convert the global sleep
  id hash table to a per-cpu hash table and use cpu-localization for all access
  to the hash table.  Note that the timeout code is also per-cpu and will
  issue the timeout callback on the correct cpu.
  On an SMP box, this code is actually more efficient then the old code.
  Instead of having to send multiple IPI messages by calling lwkt_schedule()
  on each foreign thread, we now send one IPI message to the target cpu and
  lwkt_schedule() is localized only for matching threads on that cpu.
  wakeup_one() continues to be supported.  We pass a flag and chain through
  the cpus until we exhaust available cpus or locate a match.  Currently we
  do not round-robin the cpu mask check, so this could use some improvement.
  A global cpumask array has been added so only cpus possibly containing
  the sleeping threads are chained.  We chain the IPI rather then broadcast
  it to reduce latency on the originating wakeup() and to introduce a
  staggered wakeup between cpus that may reduce resource collisions when
  multiple threads are blocked on the same resource.
  This code uses the same cpu-localization concepts that much of the rest of
  DragonFly uses for SMP, which means no mutexes, no locks, and virtually no
  added overhead in the same-cpu case, and a simple asynchronous send-and-forget
  IPI message for the SMP case.
  Revision  Changes    Path
  1.50      +1 -5      src/sys/kern/init_main.c
  1.51      +169 -25   src/sys/kern/kern_synch.c
  1.40      +4 -0      src/sys/sys/globaldata.h
  1.29      +4 -0      src/sys/sys/param.h
  1.71      +1 -1      src/sys/sys/proc.h
  1.25      +4 -4      src/sys/sys/thread2.h

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