[pve-devel] bad virtio nic performance on kvm smp guests with debian squeeze kernel

[Alexandre DERUMIER]

Yes, I have seem same behaviour,

bad network performance, or high cpu load with a lot of traffic.

I have installed 3.2 kernel from squeeze-backport, problem solved.

It should be a problem with virtio driver version.

Maybe the qemu-mailing have an idea ?


----- Mail original ----- 

De: "Martin Maurer" <martin at proxmox.com> 
À: pve-devel at pve.proxmox.com 
Envoyé: Vendredi 2 Novembre 2012 10:38:27 
Objet: [pve-devel] bad virtio nic performance on kvm smp guests with debian squeeze kernel 

Hi, 

we have significant network performance with issue with virtio_net in Debian Squeeze KVM guests, with more than one core assigned. 

I test: 
> wget -O /dev/null http://mirror/proxmox-ve_2 .2-7f9cfa4c-28.iso 

KVM guest (4 core) with e1000 Squeeze (amd64): 64.3 MB/s 
KVM guest (4 core) with virtio Squeeze (amd64): 7.34 MB/s 
KVM guest (1 core) with virtio Squeeze (amd64): 75.3 MB/s 

Kernel used in KVM guest: 2.6.32-5-amd64 #1 SMP Sun Sep 23 10:07:46 UTC 2012 x86_64 GNU/Linux 
modinfo virtio_net 

filename: /lib/modules/2.6.32-5-amd64/kernel/drivers/net/virtio_net.ko 
license: GPL 
description: Virtio network driver 
alias: virtio:d00000001v* 
depends: virtio 
vermagic: 2.6.32-5-amd64 SMP mod_unload modversions 
parm: napi_weight:int 
parm: csum:bool 
parm: gso:bool 

Proxmox VE as KVM guest is not affected, also newer Debian Kernel (e.g. Wheezy) are working without problems. 

Any ideas? 

Martin 

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