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Date:      Wed, 9 Sep 2009 09:34:13 +0000 (UTC)
From:      Attilio Rao <attilio@FreeBSD.org>
To:        cvs-src-old@freebsd.org
Subject:   cvs commit: src/sys/kern kern_lock.c kern_rwlock.c kern_sx.c
Message-ID:  <200909090934.n899YLB0018756@repoman.freebsd.org>

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attilio     2009-09-09 09:34:13 UTC

  FreeBSD src repository

  Modified files:        (Branch: RELENG_8)
    sys/kern             kern_lock.c kern_rwlock.c kern_sx.c 
  Log:
  SVN rev 197024 on 2009-09-09 09:34:13Z by attilio
  
  Adaptive spinning for locking primitives, in read-mode, have some tuning
  SYSCTLs which are inappropriate for a daily use of the machine (mostly
  useful only by a developer which wants to run benchmarks on it).
  Remove them before the release as long as we do not want to ship with
  them in.
  
  Now that the SYSCTLs are gone, instead than use static storage for some
  constants, use real numeric constants in order to avoid eventual compiler
  dumbiness and the risk to share a storage (and then a cache-line) among
  CPUs when doing adaptive spinning together.
  
  Pleasse note that the sys/linker_set.h inclusion in lockmgr and sx lock
  support could have been gone, but re@ preferred them to be in order to
  minimize the risk of problems on future merging.
  
  Please note that this patch is not a MFC, but an 'edge case' as commit
  directly to stable/8, which creates a diverging from HEAD.
  
  Tested by:      Giovanni Trematerra <giovanni dot trematerra at gmail dot com>
  Approved by:    re (kib)
  
  Revision   Changes    Path
  1.144.2.4  +11 -14    src/sys/kern/kern_lock.c
  1.48.2.4   +9 -12     src/sys/kern/kern_rwlock.c
  1.67.2.5   +8 -11     src/sys/kern/kern_sx.c



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