Re: how to increase the vnet speed?

On Tue, 23 May 2023 19:58:07 +0000
Benoit Chesneau <benoitc@enki-multimedia.eu> wrote:

> Hi all,
> 
> I've created a jail using bastille and setup network. The mainin
> terface is a 25Gbps nic and between hosts I get 24.6 Gbits/sec :

[...]

> But between one host and the jail I only get 3.96 Gbits/sec

[...]

> Is there a way to increase the performance of the of the jail? The
> nice is a mellannox ConnectX-4 Lx, mce(4) .

Modern NICs offload a lot of the protocol stack processing (checksum,
segmentation, and / or reassembly) from the CPU to dedicated silicon,
whereas inter-vnet traffic needs to be handled completely in software,
that's where the difference comes from.

Perhaps we could gain some speed by abusing mbuf flags to skip RXCSUM
for epair traffic, maybe even skip and fake TXCSUM...

Marko