[fedora-virt] Poor performace for e1000 and other fully virtualized netcard

[Cole Robinson]

On 09/05/2013 09:26 AM, Ján ONDREJ (SAL) wrote:
> Hello,
> 
>   today I disovered, that e1000 cards has very poor performance in Fedora 18
> and 19. Does not matter, if guest is an Linux or other system.
> By "poor" I mean TCP network transfers about 5-90 kB/s, even if they are on
> an gigabit network.
> 
>   By downgrading kernel on Fedora 19 from 3.10.X to
> kernel-3.9.5-301.fc19.x86_64 fixed my problem, so looks like there
> is an bug in kernel. I tested these kernels:
> 
> Fast:
> 	kernel-3.9.5-301.fc19.x86_64
> 
> Slow:
> 	kernel-3.10.7-100.fc18.x86_64
> 	kernel-3.10.9-100.fc18.x86_64
> 	kernel-3.10.10-200.fc19.x86_64
> 
> Looks like it is an change with kernel-3.10.X. I can test other kernels if
> requested.
> 
> For me, it's easy to reproduce. Tested on 4 host machines, 2 Fedoras,
> multiple kernels and different guests. Also tested some network cards,
> e1000, pcnet, ... All with similar problems.
> 
> As described in other bug, virtio net driver has time skew problems, so
> I can't use it. :-(
> 
> Any ideas, how to solve this problem?
> 

I haven't heard anything about this myself, maybe the kernel guys have a
better idea. Unless you want to try git bisect, best thing to do is file a
fedora kernel bug or try your luck upstream

- Cole