Add the ethtool counters related to RDMA/ROCE

[gangxie112]

Hi，

It seems that some important metrics in ethtool related to the RDMA/ROCE are not supported, such as tx.pause.ctrl.phy，rx.prio5.pause and etc. Those counters are very important in ROCE network and included in physical/priority port counter.

So, we we have any plan to support them?

[discordianfish]

Dunno how ethtool retrieves them but if there is a way to retrieve them not requiring privileges we're open to a PR for that

[dswarbrick]

Is tx_pause_ctrl_phy vendor or model specific? The only reference to it I can find is for the Mellanox ConnectX series of NICs which use the mlx5 driver, https://www.kernel.org/doc/html/latest/networking/device_drivers/ethernet/mellanox/mlx5/counters.html

In addition to the basic set of ethtool counters which are mature and implemented by pretty much every NIC, there are also quite a few vendor-specific ethtool stats / options.

[gangxie112]

Yes, those metrics are proprietary to specific nic vendors. But since some nics are widely used, we should at least consider some other way to support it, such as adding a plugging framework. At this time, users have to develop a agent to gather and push the metrics. This is typical way adopted by many cloud providers as far as I know.

[dswarbrick]

The textfile collector feature is arguably the "plugin framework" in node_exporter.

Implementing support natively for vendor- / hardware-specific counters is tricky without having access to said hardware for testing. I would suggest either attempting to implement this yourself (assuming that you have access to such hardware, and are a reasonably proficient Go developer), or loan some hardware to a developer who is willing to do the work.