Slow network performance since Virtio net drivers are always disabled

Bug #702040 reported by Vish Ishaya on 2011-01-12
20
This bug affects 4 people
Affects Status Importance Assigned to Milestone
OpenStack Compute (nova)
Wishlist
Unassigned

Bug Description

Right now virtio drivers are commented out which leads to abysmally slow networking. We need a flag of somesort in the kernel json (and probably image as well for whole image booting) saying whether it supports virtio.

Thierry Carrez (ttx) on 2011-01-18
summary: - Virtio net drivers do not work
+ Slow network performance since Virtio net drivers are always disabled
Changed in nova:
importance: Undecided → Wishlist
status: New → Confirmed
Vladimir Vuksan (vlists) wrote :

By default Qemu will use 8139 drivers which is 100 Mbit. If people are uncomfortable with virtio we should set the model to e1000 as that is a Gigabit interface.

Tom Fifield (fifieldt) wrote :

So, now there is a flag:

libvirt_use_virtio_for_bridges

to enable virtio on a cloud-wide basis. Is that a solution for this bug?

Though I think Vladmir has a good point - if there is no virtio, perhaps another NIC model could be more appropriate than default. You could potentially extend the virtio flag to be model choice, or try to provide best performance based on models available ...

qemu -net nic,model=? /dev/null
qemu: Supported NIC models: ne2k_pci,i82551,i82557b,i82559er,rtl8139,e1000,pcnet,virtio

Russell Bryant (russellb) wrote :

virtio is now used by default, but you can also configure it using hardware config properties on images in glance.

See:

https://blueprints.launchpad.net/nova/+spec/libvirt-custom-hardware

Changed in nova:
status: Confirmed → Fix Released
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