[ovirt-users] Network performance drop when compared to other hypervisor with vhost_net on for UDP

mad Engineer themadengin33r at gmail.com
Wed Jan 14 12:55:18 UTC 2015


Thanks Martin,
                      How can we see the changes made by tuned?
for "virtual guest" i see it changes scheduler to deadline.Is there
any way to see what parameters each  profile is going to change

Thanks

On Wed, Jan 14, 2015 at 6:14 PM, Martin Pavlík <mpavlik at redhat.com> wrote:
> Hi,
>
> from the top of my head you could try to play with tuned both with guest and host
>
> ###Install###
>  yum install tuned
>  /etc/init.d/tuned start
>  chkconfig tuned on
>
> ###usage###
> list the profile:
>  tuned-adm list
>
> change your profile:
> tuned-adm profile throughput-performance
>
> maybe try to experiment with other profiles.
>
> HTH
>
> Martin Pavlik
> RHEV QE
>
>> On 14 Jan 2015, at 12:06, mad Engineer <themadengin33r at gmail.com> wrote:
>>
>> I am running RHEL6.5 as Host and Guest on HP server.
>> Server has 128G and 48 Core[with HT enabled.]
>>
>> 3 VMs are running 2 pinned to first 24 PCPU with proper NUMA pinning,
>>
>> Guests:
>>
>> VM1:
>> 6 VCPU  pinned to 6 PCPU NUMA node 1,with 16G RAM
>>
>> VM2:
>> 6 VCPU pinned to 6 PCPU on NUMA node 0,with 16G RAM
>>
>> VM3:
>> 2 VCPU ,no pinning,4G RAM
>>
>> HOST
>> host has 10 free CPU+24 HT threads which is not allocated and is available.
>> Host also runs a small application that is single threaded,that uses ~4G RAM.
>>
>> Total resource to host is 10 CPU+24 HT=34 and 92G unallocated RAM[VMS
>> dont even use 70% of allocated RAM] also ksm is not running.
>>
>> Networking:
>> Uses linux bridge connected to 1Gbps eth0,with ip assigned on eth0
>> [This IP is called for accessing application running on host]
>> All vms use virtio and VHOST is on .
>>
>> Traffic on virtual machines are ~3MBps and combined traffic on host is ~14MBps
>>
>> "VHOST-pid-of-qemu-process" sometimes uses ~35% CPU.
>>
>>
>> There is no packet loss,drop or latency,but the issue is with the same
>> setup on Vmware with same sizing of virtual machines,with the only
>> difference as application running on host has moved to fourth VM.So in
>> Vmware there are 4 VMs.
>> Application gives better number ie on KVM that number is 310 and on
>> vmware it is 570.Application uses UDP to communicate.
>>
>> I tried removing VHOST,still value is same.(I hope VHOST-NET UDP issue
>> is solved)
>>
>> Thanks for any help
>> _______________________________________________
>> Users mailing list
>> Users at ovirt.org
>> http://lists.ovirt.org/mailman/listinfo/users
>



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