[ipxe-devel] Use iPXE's UNDI interface to read file from server very slow on virtualized guest unit

[Robin Smidsrød]

On 25.02.2014 02:52, Wang, Junhua H. (NSN - CN/Hangzhou) wrote:
>    We have a virtual machine which run on KVM, qemu on linux by SR-IOV.
> It(guest unit) use PXE to load bootloader by tftp, and then the
> bootloader will use UNDI interface to load other files from the server
> and then startup the OS
> 
>    Our problem is that when we use UNDI interface(from PXE) to load
> files, it's very slow.
> 
>    For example, after the guest os start to ready state(linux), we use
> scp cmd to copy the image from the server, it's very quick. But in the
> PXE phase, we use similiar method to copy the image from
> 
>    the server, it's very slow. Everytime, the UNDI need much more time
> to get the packet than in linux phase. From the data we captured by
> wireshark on the Ethernet port of the host machine,
> 
>    we found the data already come to the ethernet port, but the guest
> unit can't get the packet after a long time delay.
> 
>    We use SR-IOV mechinsm to do virtualization.
> 
>    The Ethernet driver we use in the PXE is igbvf.
> 
>    Question:
>                 Do you experts have some suggestions about where the
> problem may be? thanks very much! I need your help!

Maybe some of the information in this blog post might help you out.

http://blog.devicenull.org/2013/09/04/network-booting-with-sr-iov.html

-- Robin