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9c48d517ce
linux/arch/x86/kvm
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Wanpeng Li 9c48d517ce KVM: X86: Reduce the overhead when lapic_timer_advance is disabled 
When I run ebizzy in a 32 vCPUs guest on a 32 pCPUs Xeon box, I can observe
~8000 kvm_wait_lapic_expire CurAvg/s through kvm_stat tool even if the advance
tscdeadline hrtimer expiration is disabled. Each call to wait_lapic_expire()
will consume ~70 cycles when a timer fires since apic_timer_expire() will
set expired_tscdeadline and then wait_lapic_expire() will do some caculation
before bailing out. So total ~175us per second is lost on this 3.2Ghz machine.
This patch reduces the overhead by skipping the function wait_lapic_expire()
when lapic_timer_advance is disabled.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-12-14 09:26:48 +01:00
..
cpuid.c KVM: Expose new cpu features to guest 2017-12-14 09:26:45 +01:00
cpuid.h KVM: x86: Fix CPUID function for word 6 (80000001_ECX) 2017-11-17 13:20:22 +01:00
debugfs.c kvm: x86: export TSC information to user-space 2016-09-16 16:57:48 +02:00
emulate.c KVM: x86: emulate RDPID 2017-12-14 09:26:40 +01:00
hyperv.c KVM: X86: implement the logic for spinlock optimization 2017-08-08 10:57:43 +02:00
hyperv.h kvm: x86: hyperv: make VP_INDEX managed by userspace 2017-07-14 16:28:18 +02:00
i8254.c KVM: x86: take slots_lock in kvm_free_pit 2017-07-12 22:38:26 +02:00
i8254.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
i8259.c KVM: x86: simplify pic_ioport_read() 2017-04-12 20:17:15 +02:00
ioapic.c KVM: x86: ioapic: Preserve read-only values in the redirection table 2017-11-17 13:20:21 +01:00
ioapic.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
irq_comm.c KVM: x86: don't hold kvm->lock in KVM_SET_GSI_ROUTING 2017-05-02 14:45:45 +02:00
irq.c KVM: x86: get rid of pic_irqchip() 2017-04-12 20:17:13 +02:00
irq.h KVM: x86: don't hold kvm->lock in KVM_SET_GSI_ROUTING 2017-05-02 14:45:45 +02:00
Kconfig License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
kvm_cache_regs.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
lapic.c KVM: lapic: Fixup LDR on load in x2apic 2017-11-27 17:32:53 +01:00
lapic.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
mmu_audit.c KVM: x86: MMU: make array audit_point_name static 2017-12-14 09:26:41 +01:00
mmu.c x86: kvm: mmu: make kvm_mmu_clear_all_pte_masks static 2017-12-14 09:26:41 +01:00
mmu.h First batch of KVM changes for 4.15 2017-11-16 13:00:24 -08:00
mmutrace.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
mtrr.c KVM: x86: generalize guest_cpuid_has_ helpers 2017-08-07 16:11:50 +02:00
page_track.c locking/atomics: COCCINELLE/treewide: Convert trivial ACCESS_ONCE() patterns to READ_ONCE()/WRITE_ONCE() 2017-10-25 11:01:08 +02:00
paging_tmpl.h KVM: x86: extend usage of RET_MMIO_PF_* constants 2017-10-12 14:01:56 +02:00
pmu_amd.c perf/x86/amd: Make HW_CACHE_REFERENCES and HW_CACHE_MISSES measure L2 2016-09-16 16:19:49 +02:00
pmu_intel.c KVM: x86/vPMU: fix undefined shift in intel_pmu_refresh() 2017-05-19 19:59:27 +02:00
pmu.c KVM: x86: never specify a sample period for virtualized in_tx_cp counters 2017-03-01 14:19:46 +01:00
pmu.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
svm.c KVM: x86: add support for emulating UMIP 2017-12-14 09:26:39 +01:00
trace.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
tss.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
vmx.c KVM: VMX: Cache IA32_DEBUGCTL in memory 2017-12-14 09:26:47 +01:00
x86.c KVM: X86: Reduce the overhead when lapic_timer_advance is disabled 2017-12-14 09:26:48 +01:00
x86.h KVM: x86: simplify kvm_mwait_in_guest() 2017-12-14 09:26:43 +01:00