linux/arch/x86
Zhai, Edwin 4b8d54f972 KVM: VMX: Add support for Pause-Loop Exiting
New NHM processors will support Pause-Loop Exiting by adding 2 VM-execution
control fields:
PLE_Gap    - upper bound on the amount of time between two successive
             executions of PAUSE in a loop.
PLE_Window - upper bound on the amount of time a guest is allowed to execute in
             a PAUSE loop

If the time, between this execution of PAUSE and previous one, exceeds the
PLE_Gap, processor consider this PAUSE belongs to a new loop.
Otherwise, processor determins the the total execution time of this loop(since
1st PAUSE in this loop), and triggers a VM exit if total time exceeds the
PLE_Window.
* Refer SDM volume 3b section 21.6.13 & 22.1.3.

Pause-Loop Exiting can be used to detect Lock-Holder Preemption, where one VP
is sched-out after hold a spinlock, then other VPs for same lock are sched-in
to waste the CPU time.

Our tests indicate that most spinlocks are held for less than 212 cycles.
Performance tests show that with 2X LP over-commitment we can get +2% perf
improvement for kernel build(Even more perf gain with more LPs).

Signed-off-by: Zhai Edwin <edwin.zhai@intel.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2009-12-03 09:32:17 +02:00
..
boot x86: Document linker script ASSERT() quirk 2009-10-16 07:18:46 +02:00
configs tracing: Rename FTRACE_SYSCALLS for tracepoints 2009-08-26 00:17:35 +02:00
crypto crypto: aesni-intel - Fix irq_fpu_usable usage 2009-10-20 16:20:47 +09:00
ia32 x86-64: Fix register leak in 32-bit syscall audting 2009-10-26 16:23:26 +01:00
include/asm KVM: VMX: Add support for Pause-Loop Exiting 2009-12-03 09:32:17 +02:00
kernel Merge remote branch 'tip/x86/entry' into kvm-updates/2.6.33 2009-12-03 09:30:06 +02:00
kvm KVM: VMX: Add support for Pause-Loop Exiting 2009-12-03 09:32:17 +02:00
lguest lguest: move panic notifier registration to its expected place. 2009-09-23 22:26:44 +09:30
lib x86: Don't generate cmpxchg8b_emu if CONFIG_X86_CMPXCHG64=y 2009-10-01 08:42:24 +02:00
math-emu
mm x86: Fix error return sequence in __ioremap_caller() 2009-11-08 12:48:58 +01:00
oprofile perf: Do the big rename: Performance Counters -> Performance Events 2009-09-21 14:28:04 +02:00
pci const: mark struct vm_struct_operations 2009-09-27 11:39:25 -07:00
power x86: Remove final bits of CONFIG_X86_OLD_MCE 2009-09-18 08:31:23 +02:00
vdso kbuild: rename ld-option to cc-ldoption 2009-09-20 12:27:42 +02:00
video
xen xen: mask extended topology info in cpuid 2009-11-03 11:09:12 -08:00
Kbuild x86: standardize Kbuild rules 2009-04-16 18:09:02 +02:00
Kconfig Merge remote branch 'tip/x86/entry' into kvm-updates/2.6.33 2009-12-03 09:30:06 +02:00
Kconfig.cpu x86: Side-step lguest problem by only building cmpxchg8b_emu for pre-Pentium 2009-10-26 12:33:02 +01:00
Kconfig.debug kmemcheck: make kconfig accessible for other architectures 2009-06-15 15:49:17 +02:00
Makefile x86: Remove STACKPROTECTOR_ALL 2009-10-23 16:35:23 +02:00
Makefile_32.cpu x86: add specific support for Intel Atom architecture 2009-08-23 11:20:02 +02:00