[PATCH] i386: vMI timer patches

VMI timer code.  It works by taking over the local APIC clock when APIC is
configured, which requires a couple hooks into the APIC code.  The backend
timer code could be commonized into the timer infrastructure, but there are
some pieces missing (stolen time, in particular), and the exact semantics of
when to do accounting for NO_IDLE need to be shared between different
hypervisors as well.  So for now, VMI timer is a separate module.

[Adrian Bunk: cleanups]

Subject: VMI timer patches
Signed-off-by: Zachary Amsden <zach@vmware.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Andi Kleen <ak@suse.de>
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>

1 files changed, 9 insertions, 0 deletions

diff --git a/arch/i386/Kconfig b/arch/i386/Kconfig
index a3b3f6ee3642..595fb771366e 100644
--- a/arch/i386/Kconfig
+++ b/arch/i386/Kconfig
@@ -1272,3 +1272,12 @@ config X86_TRAMPOLINE
 config KTIME_SCALAR
         bool
         default y
+
+config NO_IDLE_HZ
+        bool
+        depends on PARAVIRT
+        default y
+        help
+          Switches the regular HZ timer off when the system is going idle.
+          This helps a hypervisor detect that the Linux system is idle,
+          reducing the overhead of idle systems.