ethbw(X)

💖 ethbw — the NIC bandwidth bestie 💖

okay so ethbw is from the EFSFFCLIRG man page crew and it is literally the group chat of your RDMA NICs. It reports the total data moved per RDMA NIC over each interval (default of 1 second, bestie, one whole second). The bandwidth reported for each interval is in units of MB (1,000,000 bytes) over the interval — yes, that's the decimal MB, not the nerdy binary one, iykyk. 🌸

Both transmit (xmt) and receive (rcv) bandwidth counters are monitored. Iconic. ethbw also monitors Intel NICs for any RDMA retransmit or input packet discards, in which case, the xmt or rcv, respectively, is shown as red. 🚨 So if you see red, that's not a vibe, that's a signal.

The data is gathered via data movement counters in /sys/class/infiniband. Slay, filesystem. 💅

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🎀 When you might need to improve PFC tuning 🎀

The following cases may present the need to improve PFC tuning:

1. Retransmits can represent packet loss or corruption in the network and may indicate opportunities to improve PFC tuning or high bit error rates (BER) on some cables or devices.
2. Input packet discards indicate packets the NIC itself dropped upon receipt. This can represent opportunities to improve PFC tuning but can also be normal for some environments. Retransmits at the remote NICs that are communicating with this NIC are a more powerful indicator of PFC or BER causes for packet loss.

ngl, case 1 is the "your cable is giving dust" situation and case 2 is sometimes just... Tuesday. Don't panic. 🫶

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✨ Syntax ✨

ethbw [-i  seconds] [-d  seconds] [ nic ... ]

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💅 Options 💅

• --help — Produces full help text. Your girl is helpful like that. 💖
• -i, --interval seconds — Specifies the interval at which bandwidth will be shown. Values of 1-60 allowed. Defaults to 1. Keep it in range, bestie, the NICs have boundaries. 🎀
• -d, --duration seconds — Specifies the duration to monitor. Default is infinite. Infinite. Main character energy fr fr — it will simply never stop unless you tell it to. 😭
• nic — Specifies an RDMA NIC name. If no NICs are specified, all RDMA NICs will be monitored. The "I'll just watch everyone" default. 👑

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🦋 Examples 🦋

Watch everything forever (the default maximalist move):

ethbw

Watch a couple of specific NICs, because you have favorites:

ethbw irdma1 irdma3

Slow the interval down to 2 seconds and dip out after 300, a very sensible, very adult thing to do:

ethbw -i 2 -d 300 irdma1 irdma3

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Remember: the xmt or rcv going red means retransmits or input packet discards showed up on an Intel NIC. It's giving maybe check your PFC tuning or BER. Not a drill, but also not necessarily a crisis. 💀

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Copyright(C) 2020-2024 Intel Corporation — ethbw(X)

and that's the whole page, bestie 💜 thanks for reading, go check your counters, you ate. 🍓✨