net: disable WiFi power save by default

[Sergio-N-Jr]

Adds a NetworkManager configuration to disable WiFi power saving by default.

Power save mode introduces latency spikes and inconsistent throughput,
which conflicts with CachyOS's focus on responsiveness. This is a common
tweak recommended for gaming and low-latency workloads.

The setting uses NetworkManager's native configuration instead of iw
commands, so it works regardless of the interface name (wlan0, wlp3s0, etc.)
and is applied automatically on reconnect.

wifi.powersave = 2 → disabled
wifi.powersave = 3 → enabled (NM default)

[1Naim]

Power save mode introduces latency spikes and inconsistent throughput

How bad is it? Do you have some results?

[Sergio-N-Jr]

Yes, it's quite noticeable.

With power save enabled, my ping to the local router (192.168.x.x) was consistently spiking even on a local network with no internet involved.

After applying wifi.powersave = 2, the latency dropped significantly and became stable.

This is especially relevant for gaming and any low-latency workload, which aligns well with CachyOS's performance focus.

[1Naim]

I'm asking for the numbers here.

[Sergio-N-Jr]

Yes!

Here are some quick numbers from my local router ping test (192.168.0.1).

Power Save ON
Samples: 250, 270, 289, 309, 329, 351, 374, 387, 408 ms
Average: 329.7 ms

Power Save OFF
Samples: 134, 153, 172, 188, 210 ms
Average: 171.4 ms

Difference
Disabling power save reduced average latency by ~158 ms (about 48% lower).

[Revival8697]

Power Save OFF
Samples: 134, 153, 172, 188, 210 ms
Average: 171.4 ms

So min/avg/max/mdev = 134/171.4/210/26.46 ms. That is bad.

Disabling power save reduced average latency by ~158 ms (about 48% lower).

It is still bad, you should fix your network. Here is mine:

• Power save on: rtt min/avg/max/mdev = 9.866/11.161/15.150/1.544 ms
• Power save off: rtt min/avg/max/mdev = 1.979/2.938/7.430/1.629 ms

[Sergio-N-Jr]

Yes, you're right — the latency is still bad in that state, and my network setup clearly needs further tuning.

I found that the following command fixes the issue completely on my side:

sudo iw dev wlan0 set txpower fixed 2000

After applying it, my average ping drops to around 5–7 ms, making the connection stable again.

So in my case:

Power save OFF already reduces latency significantly.
TX power adjustment removes the remaining problem.

However, this commit is only about disabling power save, since that is a much safer and more universal default.

Changing TX power may involve regulatory restrictions depending on the country, device, or driver support, so I still need to research it properly before recommending it as a system default.

Once I finish testing and studying it further, I may open another PR with a possible complete solution.

[Sergio-N-Jr]

Anyway, for now, temporarily setting Power Save OFF by default would likely help many users.

[mati865]

I had similar power saving issues with Qualcomm NCM865 (numbers in the name are just a coincidence) last year. Wi-Fi would struggle to achieve 100 Mb/s and the latency was jittery. Eventually it got fixed in the kernel/firmware and works fine now:

❯ trip -m pretty 192.168.50.1
┌─────┬──────────────┬─────────────────────┬───────┬─────┬──────┬──────┬─────┬──────┬──────┬────────┐
│ Hop ┆ IPs          ┆ Addrs               ┆ Loss% ┆ Snt ┆ Recv ┆ Last ┆ Avg ┆ Best ┆ Wrst ┆ StdDev │
╞═════╪══════════════╪═════════════════════╪═══════╪═════╪══════╪══════╪═════╪══════╪══════╪════════╡
│ 1   ┆ 192.168.50.1 ┆ RT-AX59U-BA32.local ┆ 0.0   ┆ 10  ┆ 10   ┆ 3.4  ┆ 2.9 ┆ 2.2  ┆ 4.1  ┆ 0.5    │
└─────┴──────────────┴─────────────────────┴───────┴─────┴──────┴──────┴─────┴──────┴──────┴────────┘

This is over 5 GHz at -64 dBm signal level with power save on.

I recommend monitoring how your adapter behaves during normal desktop usage and during stress scenarios like speedtest.net with wavemon tool and reporting the issue with the findings at the kernel bug tracker and to your adapter manufacturer.

[ventureoo]

I would prefer if it possible to go away from NetworkManager configuration and use udev rule for that.

[1Naim]

I would prefer if it possible to go away from NetworkManager configuration and use udev rule for that.

I agree, it should enable powersaving (or whatever the default is) when running on battery.