git: kernel - Properly account system time for contending tokens

[Matthew Dillon <dillon@xxxxxxxxxxxxxxxxxxxxxxx>]

commit e2b925335d50b652b228d64c07f94863aee95dab
Author: Matthew Dillon <dillon@apollo.backplane.com>
Date:   Tue Feb 19 22:56:58 2013 -0800

    kernel - Properly account system time for contending tokens
    
    * When the LWKT schedule gets stuck on a contending token it switches
      through the idle thread, the idle thread is told not to halt, and
      resolution of the contention is handled by lwkt_switch() from the
      idle thread's context.
    
    * This was causing token contention to be improperly accounted for as
      idle time in the per-cpu stats.  Fix the case by testing the
      RQF_AST_LWKT_RESCHED flag which tells the idle thread not to halt,
      and account for the tick as system time if the flag is set.
    
    * The improper time accounting was causing powerd to come to the wrong
      conclusion in massively parralel fsstress tests on monster.dragonflybsd.org
      (48 cpus).  With the fix, powerd no longer becomes confused.
    
    Reported-by: vsrinivas

Summary of changes:
 sys/kern/kern_clock.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

http://gitweb.dragonflybsd.org/dragonfly.git/commitdiff/e2b925335d50b652b228d64c07f94863aee95dab


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