Poor virtio performance

[zefie]

Host: Fedora 14 x86_64
Guest tested: Windows Server 2003

Benchmark via ddrescue and /dev/zero


Using virtio (virtio-win-1.1.16 driver):

Code: Select all

[root@hailey hda]# ddrescue /dev/zero tmp2/test.bin

Press Ctrl-C to interrupt
rescued:   103088 kB,  errsize:       0 B,  current rate:    3604 kB/s
   ipos:   103088 kB,   errors:       0,    average rate:    3160 kB/s
   opos:   103088 kB,     time from last successful read:       0 s
Copying non-tried blocks...
Interrupted by user

Using Intel PRO/1000 MT Desktop (82540EM):

Code: Select all

[root@hailey hda]# ddrescue /dev/zero tmp2/test.bin

Press Ctrl-C to interrupt
rescued:   310116 kB,  errsize:       0 B,  current rate:   17760 kB/s
   ipos:   310116 kB,   errors:       0,    average rate:   16791 kB/s
   opos:   310116 kB,     time from last successful read:       0 s
Copying non-tried blocks...
Interrupted by user

Tests using file transfers (DVD ISO) in Midnight Commander show about half of that. About 2mB - 4mB/s for virtio (and minimal cpu usage) and about 10mB/s steady for Intel (high cpu usage).

Am I doing something wrong?

[badadmin]

On your Windows guest, right click on the adapter, go to properties and select "Configure..." for the Red Hat VirtIO Ethernet Adapter. Under the advanced section what do you see listed under "Connection rate (Mb)"? It has three options there for 10M, 100M, and 1G. Can't say for certain if that is your issue but that would be my first guess.

[zefie]

Hi, I no longer have the VM in question but I do recall tweaking the parameters there, There were 4 options actually, "10M", "100M", "1G", "1G".. Why there were two 1G I am not sure, maybe a placeholder for 10G? Either way both 1G connected at 1.0gbit and had the same speed. The speeds in my OP post were at the supposed 1gbit.

I can say this though, my performance with a Windows host and a Linux guest are much better than this. It may just have been an issue with Fedora.