So I think I have figured out some things Theo browsing through https://github.com/openbsd/src/blob/master/sys/dev/pci/if_mcx.c.
I can see that some offloading is supported, but have not yet figured out how much is implemented yet. It looks like the offloading capability in these cards are much more granular than I have understood from previous hardware. I was able to decipher some of it using this https://www.mellanox.com/related-docs/user_manuals/Ethernet_Adapters_Programming_Manual.pdf (this is very well written). And I was quite excited to see what looks like the RDMA access support in the mcx driver! So we should be able to see the super low latency capabilities with this card :) I will keep pushing myself.. Thanks again Theo On Wed, Sep 29, 2021 at 2:21 PM Andrew Lemin <andrew.le...@gmail.com> wrote: > Hi Theo :) > > Ok sure, I will put on my cape-of-courage and start reading the source.. I > may be some time! > > On Wed, Sep 29, 2021 at 1:56 PM Theo de Raadt <dera...@openbsd.org> wrote: > >> We tend to keep our driver manual pages without detailed promises. >> They do ethernet, they do it best effort, etc. >> >> What you want to know can be found by reading the source, or the >> commit logs. Since this is a locally written driver, the code is >> surprisingly approachable. >> >> Andrew Lemin <andrew.le...@gmail.com> wrote: >> >> > Hi. I hope everyone is well and having a great day :) >> > >> > Just a quick question about the mcx (Mellanox 5th generation Ethernet >> > device) drivers >> > https://man.openbsd.org/mcx.4 >> > >> > The man page says nothing more than it supports; >> > ConnectX-4 Lx EN >> > ConnectX-4 EN >> > ConnectX-5 EN >> > ConnectX-6 EN >> > >> > I am looking for some clarity on what features and performance >> > characteristics mcx boasts? >> > >> > For example are the following basic hardware features supported by this >> > driver? >> > IPv4 receive IP/TCP/UDP checksum offload >> > IPv4 transmit TCP/UDP checksum offload >> > VLAN tag insertion and stripping >> > interrupt coalescing >> > >> > And what other features does it support? >> > >> > I also came across a comment in some forum a while back (so high quality >> > information 😉) that mentioned Mellanox drivers in OpenBSD are SMP safe >> and >> > so not giant-locked. Is this true? >> > >> > Thanks, Andy, >> >
