Re: how to increase the vnet speed?

> On May 24, 2023, at 5:15 AM, Marko Zec <zec@fer.hr> wrote:
> 
> 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...

For epair I think it is doable.

Other hardware offload features such as VLAN_HWTAGGING can be also
taken into account.

> 
> Marko
> 

Best regards,
Zhenlei