Wanpeng Li c5ce8235cf KVM: VMX: Optimize tscdeadline timer latency ... 'Commit d0659d946b ("KVM: x86: add option to advance tscdeadline hrtimer expiration")' advances the tscdeadline (the timer is emulated by hrtimer) expiration in order that the latency which is incurred by hypervisor (apic_timer_fn -> vmentry) can be avoided. This patch adds the advance tscdeadline expiration support to which the tscdeadline timer is emulated by VMX preemption timer to reduce the hypervisor lantency (handle_preemption_timer -> vmentry). The guest can also set an expiration that is very small (for example in Linux if an hrtimer feeds a expiration in the past); in that case we set delta_tsc to 0, leading to an immediately vmexit when delta_tsc is not bigger than advance ns. This patch can reduce ~63% latency (~4450 cycles to ~1660 cycles on a haswell desktop) for kvm-unit-tests/tscdeadline_latency when testing busy waits. Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Wanpeng Li <wanpengli@tencent.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>		2018-06-04 17:51:59 +02:00
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alpha
arc
arm	kvm: Make VM ioctl do valloc for some archs	2018-06-01 19:18:26 +02:00
arm64	kvm: Make VM ioctl do valloc for some archs	2018-06-01 19:18:26 +02:00
c6x
h8300
hexagon
ia64
m68k
microblaze
mips	kvm: Change return type to vm_fault_t	2018-06-01 19:18:25 +02:00
nds32
nios2
openrisc
parisc	parisc: Fix section mismatches	2018-05-02 21:47:35 +02:00
powerpc	kvm: no need to check return value of debugfs_create functions	2018-06-01 19:18:27 +02:00
riscv
s390	kvm: Change return type to vm_fault_t	2018-06-01 19:18:25 +02:00
sh	sh: switch to NO_BOOTMEM	2018-05-11 13:35:46 -04:00
sparc
um
unicore32
x86	KVM: VMX: Optimize tscdeadline timer latency	2018-06-04 17:51:59 +02:00
xtensa
.gitignore
Kconfig	KASAN: prohibit KASAN+STRUCTLEAK combination	2018-05-11 17:28:45 -07:00