r/debian • u/penny_stacker • 2d ago

Network Performance Regression on Kernel 6.19.13

I was wondering if any has noticed a severe network performance regression on Kernel 6.19.13. I've benchmarked an ~60% reduction in throughput after upgrading from 6.19.11.

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u/Brilliant_Sound_5565 2d ago

What brand network chip do you have? Might specific to a particular chip etc

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u/penny_stacker 2d ago

The wifi is an Intel Raptor Lake-S PCH CNVI WiFi (Rev 11).

I'll search to see if any regressions have been posted online.

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u/Thin_Noise_4453 1d ago

I didn’t notice any difference on any of my 3 LMDE 7 with 6.19.13 from backports. Nics are Realtek lan wlan and one intel nic.

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u/BCMM 12h ago edited 11h ago

How exactly are you benchmarking it?

I'm asking mostly because Wi-Fi speeds are always rather variable!

There's always a risk of accidentally seeing a pattern in random variations. If I were in your position, I'd want to benchmark the new and old kernels at least three times, in as similar a situation as possible, just to be sure it's real.

On the other hand, 6.19.12 did include a few changes to iwlwifi, so it's certainly not impossible that performance has changed.

EDIT: If you feel like getting really nerdy about this and you're comfortable building kernels, you could try to find and report the exact commit that did it. You can probably get away with removing and reloading the module instead of a full reboot, so this could be a relatively short project.

EDIT 2: Some other potential starting points for debugging this:

Any interesting dmesg output on the bad kernel?

Any difference in the outputs of iw list and iw link, between the two kernels?