K 10
svn:author
V 3
mav
K 8
svn:date
V 27
2012-07-20T19:35:20.078798Z
K 7
svn:log
V 888
Partially MFC r212541:
Refactor cpu_idle() on x86.
Use MONITOR/MWAIT instrunctions (if supported) under high sleep/wakeup rate,
as fast alternative to other methods.  It allows SMP scheduler to wake up
sleeping CPUs much faster without using IPI, significantly increasing
performance on some highly task-switching loads.  Also on such loads it
hides two ACPI timer reads, otherwise done by acpi_cpu_idle(), that are
reported to be slow on some systems.

MFC r225936 (by attilio):
Add some improvements in the idle table callbacks:
- Replace instances of manual assembly instruction "hlt" call
  with halt() function calling.
- In cpu_idle_mwait() avoid races in check to sched_runnable() using
  the same pattern used in cpu_idle_hlt() with the 'hlt' instruction.
- Add comments explaining the logic behind the pattern used in
  cpu_idle_hlt() and other idle callbacks.

PR:		kern/170021

END