sorry,i take mistake,
the ept violation is not caused by 2M hugepages, but caused by e1000
emulated by qemu.
I test uesd 2M hugepages and virio, the performance is better than
e1000. but is still worse than xen. I will continue to find out other
reason.
so, there are two question:
1.why have so many ept violation when used e1000?
2.when used virtio, there ara also such error happen.is this normal?
I add the printk in function tdp_page_fault below.
pfn = gfn_to_pfn(vcpu->kvm, gfn);
if (is_error_pfn(pfn)) {
kvm_release_pfn_clean(pfn);
if( printk_ratelimit() ) {
printk(KERN_EMERG "error gpa is %ld\n", gpa);
}
return is_fault_pfn(pfn) ? -EFAULT : 1;
}
and result is:
[root@rhel6-kvm1 ~]# dmesg -c
__ratelimit: 387 callbacks suppressed
error gpa is 4273995776
error gpa is 4273995776
error gpa is 4273995776
error gpa is 4273995776
error gpa is 4273995776
2010/11/9 lidong chen <chen.lidong.kernel@xxxxxxxxx>:
>> What workload is this? Are you using virtio?
> yes,i using virtio and vhost. the cpu rate is 70%.
>
> I found it maybe caused by 2M HugePages. if didn't use 2M
> HugePages, there are no vm exits caused by ept violation.
>
> I will test the performance without 2M Hugepages later, and see why
> HugePage cause such a result.
>
>
> 2010/11/8 Avi Kivity <avi@xxxxxxxxxx>:
>> On 11/08/2010 02:15 PM, lidong chen wrote:
>>>
>>> I run my application both on xen and kvm, and I found the performance
>>> on kvm is worse than xen.
>>>
>>> kvm: 2.6.32-60.el6.x86_64 redhat 6 bate 2
>>> xen: xen3.4.2
>>>
>>> then i stat the vm exit reason, and i found the ept violation reason,
>>> kvm is much more than xen. the static result is :
>>>
>>> __ratelimit: 387 callbacks suppressed
>>> error gpa is 4273995776
>>> error gpa is 4273995776
>>> error gpa is 4273995776
>>> error gpa is 4273995776
>>> error gpa is 4273995776
>>
>> fec00000, this is the IOAPIC.
>>
>> What workload is this? Are you using virtio?
>>
>>> error gpa is 782336
>>> error gpa is 782336
>>> error gpa is 782336
>>> error gpa is 782336
>>> error gpa is 782336
>>> __ratelimit: 387 callbacks suppressed
>>> error gpa is 782336
>>> error gpa is 782336
>>> error gpa is 782336
>>> error gpa is 782336
>>> error gpa is 782336
>>> error gpa is 782336
>>> error gpa is 782336
>>> error gpa is 782336
>>> error gpa is 782336
>>> error gpa is 782336
>>>
>>
>> bf000, this is the display. What display mode are you using? is the
>> workload display intensive?
>>
>> Please provide reports using
>>
>> $ trace-cmd record -e kvm:kvm_page_fault
>> ^C
>> $ trace-cmd report
>>
>>
>> --
>> error compiling committee.c: too many arguments to function
>>
>>
>
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