hi,Avi:
I met the same problem, tons of hpet vm_exits(vector 209, fault
address is in the guest vm's hpet mmio range), even I disable hpet
device in win7 guest vm, it still produce a larget amount of vm_exits
when trace-cmd ; I add -no-hpet to start the vm, it still has HPET
device inside VM.
Does that means the HPET device in VM does not depend on the
emulated hpet device in qemu-kvm? Is there any way to disable the VM
HPET device to prevent so many vm_exits? Thansk.
Regards.
Suya.
2009/12/3 Avi Kivity <avi@xxxxxxxxxx>:
> On 12/03/2009 03:46 PM, Andrew Theurer wrote:
>>
>> I am running a windows workload which has 26 windows VMs running many
>> instances of a J2EE workload. There are 13 pairs of an application server
>> VM and database server VM. There seem to be quite a bit of vm_exits, and it
>> looks over a third of them are mmio_exit:
>>
>>> efer_relo 0
>>> exits 337139
>>> fpu_reloa 247321
>>> halt_exit 19092
>>> halt_wake 18611
>>> host_stat 247332
>>> hypercall 0
>>> insn_emul 184265
>>> insn_emul 184265
>>> invlpg 0
>>> io_exits 69184
>>> irq_exits 52953
>>> irq_injec 48115
>>> irq_windo 2411
>>> largepage 19
>>> mmio_exit 123554
>>
>> I collected a kvmtrace, and below is a very small portion of that. Is
>> there a way I can figure out what device the mmio's are for?
>
> We want 'info physical_address_space' in the monitor.
>
>> Also, is it normal to have lots of ept_violations? This is a 2 socket
>> Nehalem system with SMT on.
>
> So long as pf_fixed is low, these are all mmio or apic accesses.
>
>>
>>
>>> qemu-system-x86-19673 [014] 213577.939624: kvm_page_fault: address
>>> fed000f0 error_code 181
>>> qemu-system-x86-19673 [014] 213577.939627: kvm_mmio: mmio
>>> unsatisfied-read len 4 gpa 0xfed000f0 val 0x0
>>> qemu-system-x86-19673 [014] 213577.939629: kvm_mmio: mmio read len 4 gpa
>>> 0xfed000f0 val 0xfb8f214d
>
> hpet
>
>>> qemu-system-x86-19673 [014] 213577.939631: kvm_entry: vcpu 0
>>> qemu-system-x86-19673 [014] 213577.939633: kvm_exit: reason
>>> ept_violation rip 0xfffff8000160ef8e
>>> qemu-system-x86-19673 [014] 213577.939634: kvm_page_fault: address
>>> fed000f0 error_code 181
>
> hpet - was this the same exit? we ought to skip over the emulated
> instruction.
>
>>> qemu-system-x86-19673 [014] 213577.939693: kvm_page_fault: address
>>> fed000f0 error_code 181
>>> qemu-system-x86-19673 [014] 213577.939696: kvm_mmio: mmio
>>> unsatisfied-read len 4 gpa 0xfed000f0 val 0x0
>
> hpet
>
>>> qemu-system-x86-19332 [008] 213577.939699: kvm_exit: reason
>>> ept_violation rip 0xfffff80001b3af8e
>>> qemu-system-x86-19332 [008] 213577.939700: kvm_page_fault: address
>>> fed000f0 error_code 181
>>> qemu-system-x86-19673 [014] 213577.939702: kvm_mmio: mmio read len 4 gpa
>>> 0xfed000f0 val 0xfb8f3da6
>
> hpet
>
>>> qemu-system-x86-19332 [008] 213577.939706: kvm_mmio: mmio
>>> unsatisfied-read len 4 gpa 0xfed000f0 val 0x0
>>> qemu-system-x86-19563 [010] 213577.939707: kvm_ioapic_set_irq: pin 11
>>> dst 1 vec=130 (LowPrio|logical|level)
>>> qemu-system-x86-19332 [008] 213577.939713: kvm_mmio: mmio read len 4 gpa
>>> 0xfed000f0 val 0x29a105de
>
> hpet ...
>
>>> qemu-system-x86-19673 [014] 213577.939908: kvm_ioapic_set_irq: pin 11
>>> dst 1 vec=130 (LowPrio|logical|level)
>>> qemu-system-x86-19673 [014] 213577.939910: kvm_entry: vcpu 0
>>> qemu-system-x86-19673 [014] 213577.939912: kvm_exit: reason apic_access
>>> rip 0xfffff800016a050c
>>> qemu-system-x86-19673 [014] 213577.939914: kvm_mmio: mmio write len 4
>>> gpa 0xfee000b0 val 0x0
>
> apic eoi
>
>>> qemu-system-x86-19332 [008] 213577.939958: kvm_mmio: mmio write len 4
>>> gpa 0xfee000b0 val 0x0
>>> qemu-system-x86-19673 [014] 213577.939958: kvm_pic_set_irq: chip 1 pin 3
>>> (level|masked)
>>> qemu-system-x86-19332 [008] 213577.939958: kvm_apic: apic_write APIC_EOI
>>> = 0x0
>
> apic eoi
>
>>> qemu-system-x86-19673 [014] 213577.940010: kvm_exit: reason cr_access
>>> rip 0xfffff800016ee2b2
>>> qemu-system-x86-19673 [014] 213577.940011: kvm_cr: cr_write 4 = 0x678
>>> qemu-system-x86-19673 [014] 213577.940017: kvm_entry: vcpu 0
>>> qemu-system-x86-19673 [014] 213577.940019: kvm_exit: reason cr_access
>>> rip 0xfffff800016ee2b5
>>> qemu-system-x86-19673 [014] 213577.940019: kvm_cr: cr_write 4 = 0x6f8
>
> toggling global pages, we can avoid that with CR4_GUEST_HOST_MASK.
>
> So, tons of hpet and eois. We can accelerate both by thing the hyper-V
> accelerations, we already have some (unmerged) code for eoi, so this should
> be improved soon.
>
>>
>> Here is oprofile:
>>
>>> 4117817 62.2029 kvm-intel.ko kvm-intel.ko
>>> vmx_vcpu_run
>>> 338198 5.1087 qemu-system-x86_64 qemu-system-x86_64
>>> /usr/local/qemu/48bb360cc687b89b74dfb1cac0f6e8812b64841c/bin/qemu-system-x86_64
>>> 62449 0.9433 kvm.ko kvm.ko
>>> kvm_arch_vcpu_ioctl_run
>>> 56512 0.8537
>>> vmlinux-2.6.32-rc7-5e8cb552cb8b48244b6d07bff984b3c4080d4bc9-autokern1
>>> vmlinux-2.6.32-rc7-5e8cb552cb8b48244b6d07bff984b3c4080d4bc9-autokern1
>>> copy_user_generic_string
>
> We ought to switch to put_user/get_user. rep movs has quite slow start-up.
>
>>> 52373 0.7911
>>> vmlinux-2.6.32-rc7-5e8cb552cb8b48244b6d07bff984b3c4080d4bc9-autokern1
>>> vmlinux-2.6.32-rc7-5e8cb552cb8b48244b6d07bff984b3c4080d4bc9-autokern1
>>> native_write_msr_safe
>
> hpet in kernel or hyper-V timers will reduce this.
>
>>> 34847 0.5264
>>> vmlinux-2.6.32-rc7-5e8cb552cb8b48244b6d07bff984b3c4080d4bc9-autokern1
>>> vmlinux-2.6.32-rc7-5e8cb552cb8b48244b6d07bff984b3c4080d4bc9-autokern1
>>> schedule
>>> 34678 0.5238
>>> vmlinux-2.6.32-rc7-5e8cb552cb8b48244b6d07bff984b3c4080d4bc9-autokern1
>>> vmlinux-2.6.32-rc7-5e8cb552cb8b48244b6d07bff984b3c4080d4bc9-autokern1
>>> fget_light
>
> and this.
>
>>> 29894 0.4516 kvm.ko kvm.ko
>>> paging64_walk_addr
>>> 27778 0.4196 kvm.ko kvm.ko
>>> gfn_to_hva
>>> 24563 0.3710 kvm.ko kvm.ko
>>> x86_decode_insn
>>> 23900 0.3610
>>> vmlinux-2.6.32-rc7-5e8cb552cb8b48244b6d07bff984b3c4080d4bc9-autokern1
>>> vmlinux-2.6.32-rc7-5e8cb552cb8b48244b6d07bff984b3c4080d4bc9-autokern1
>>> do_select
>>> 21123 0.3191 libc-2.10.90.so libc-2.10.90.so
>>> memcpy
>>> 20694 0.3126 kvm.ko kvm.ko
>>> x86_emulate_insn
>
> hyper-V APIC and timers will reduce all of the above (except memcpy).
>
> --
> error compiling committee.c: too many arguments to function
>
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