How to determine identity of obscure `nic:br-` devices in powertop?

Question

Currently, the powertop output from my computer (a thinkpad with skylake i7-6600U running ubuntu 16.04) looks like

The battery reports a discharge rate of 6.90 W
The estimated remaining time is 2 hours, 42 minutes

Summary: 425.7 wakeups/second,  3.2 GPU ops/seconds, 0.0 VFS ops/sec and 5.7% CPU use

Power est.              Usage       Events/s    Category       Description
  4.38 W      0.0 pkts/s                Device         nic:br-885189c6e63f
  1.87 W      0.0 pkts/s                Device         nic:docker0
  1.25 W      2.9 pkts/s                Device         Network interface: wlp4s0 (iwlwifi)
  495 mW      0.0 pkts/s                Device         nic:br-0a1d679ef26a
  128 mW      0.0 pkts/s                Device         nic:br-fe67a27aefc1
  118 mW      0.0 pkts/s                Device         nic:br-c18806e895c7
 58.4 mW     31.0%                      Device         Display backlight

I doubt that the per-device power usage is completely accurate. That's because, prior to cycling my wifi on and off the top power user was reported to be Network interface: wlp4s0. Nonetheless, these nic:br- devices seem like they are among the top power-using devices.

How can I figure out which devices these are?

Answer 1

These are ethernet bridge devices, and you can investigate them with the /sbin/bridge or the older /sbin/brctl utilities. You can bring them down with the traditional ifconfig <dev> down command.

In this case it looks like they are created by Docker. I recently discovered that these devices seem to persist and defy power management even if you're not immediately running Docker.