cvs commit: src/sys/sys unpcb.h src/sys/kern uipc_usrreq.c

[Robert Watson]

rwatson     2007-02-26 20:47:52 UTC

  FreeBSD src repository

  Modified files:
    sys/sys              unpcb.h 
    sys/kern             uipc_usrreq.c 
  Log:
  Revise locking strategy used for UNIX domain sockets in order to improve
  concurrency:
  
  - Add per-unpcb mutexes protecting unpcb connection state, fields, etc.
  
  - Replace global UNP mutex with a global UNP rwlock, which will protect the
    UNIX domain socket connection topology, v_socket, and be acquired
    exclusively before acquiring more than per-unpcb at a time in order to
    avoid lock order issues.
  
  In performance measurements involving MySQL, this change has little or no
  overhead on UP (+/- 1%), but leads to a significant (5%-30%) improvement in
  multi-processor measurements using the sysbench and supersmack benchmarks.
  
  Much testing by:        kris
  Approved by:            re (kensmith)
  
  Revision  Changes    Path
  1.197     +468 -222  src/sys/kern/uipc_usrreq.c
  1.22      +1 -0      src/sys/sys/unpcb.h