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#1 2021-11-17 13:32:21

Vermoot
Member
Registered: 2021-11-17
Posts: 5

Latency spikes while gaming on a Broadcom wifi card

Hello!

So I've got a Fenvi FV-HB1200 PCI-e card, which has a Broadcom BCM4360 (43a0) chipset. It works well for the most part, but I've got an issue with a particular use case, which I think might just be more general, but especially noticeable in this use case:

I play Rocket League through Proton in Steam, and it works really well, but here's the big issue: I get lag spikes every minute or so. I have a good ping (my internet connection is pretty good overall), about 30ms, but once in a while it goes up to 200ms (according to the in-game graphs) and that messes me up.

This isn't a Rocket League problem, because tryint to troubleshoot this I've tried using ethernet, which solves the issue (but I can't really use it all the time), and I've also tried playing through wifi on a windows install, there's no problem there. The problem is then only on wifi, on linux.

From what I've seen, Broadcom cards are iffy on linux, and especially those like mine that only work with the `broadcom-wl` driver. I'm still looking for a fix on this particular card though.

So now I have several questions:

- How can I try and troubleshoot this, maybe with a networking tool, to see how and when those latency spikes happen? I've tried things like ping google.com -i 0.02, and I do see some latency spikes sometimes, but I can't say for sure if it's the same thing. The problem is that online gaming like Rocket League is very sensitive to ping, so trying to reproduce it in other use cases is pretty hard.

- How can I fix this? Is there any other driver I can try, or maybe should I just try and downgrade broadcom-wl? Can I maybe try changing some settings on my router or in my network configuration to avoid those latency spikes?

Thanks for reading!

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#2 2021-11-20 22:32:11

Head_on_a_Stick
Member
From: London
Registered: 2014-02-20
Posts: 5,926
Website

Re: Latency spikes while gaming on a Broadcom wifi card

Vermoot wrote:

How can I try and troubleshoot this

Check the systemd journal.

Vermoot wrote:

How can I fix this?

Check the Broadcom page on the ArchWiki. The fact that they have their own page speaks volumes for the quality of the devices. Have you considered changing the card? tongue


There are two ways of constructing a software design: one way is to make it so simple that there are obviously no deficiencies and the other way is to make it so complicated that there are no obvious deficiencies.

— C.A.R. Hoare, The 1980 ACM Turing Award Lecture

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#3 2021-11-24 15:35:09

Vermoot
Member
Registered: 2021-11-17
Posts: 5

Re: Latency spikes while gaming on a Broadcom wifi card

Head_on_a_Stick wrote:

Check the systemd journal.

How so? Can you elaborate how that would allow me to precisely check what's making me lag?

I *can* of course change cards, but I'd prefer making sure that this can't be fixed otherwise (and that another card would fix the problem) before doing so.

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#4 2021-11-24 15:46:58

V1del
Forum Moderator
Registered: 2012-10-16
Posts: 14,469

Re: Latency spikes while gaming on a Broadcom wifi card

You should check whether the journal gives you a message coinciding with the lag, possibly from the kernel module directly or whatever daemon you are using to connect.

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#5 2021-11-24 15:48:07

Vermoot
Member
Registered: 2021-11-17
Posts: 5

Re: Latency spikes while gaming on a Broadcom wifi card

V1del wrote:

You should check whether the journal gives you a message coinciding with the lag, possibly from the kernel module directly or whatever daemon you are using to connect.

Can I somehow see that live on my second monitor while I'm playing? It might be difficult to check the right timings after the fact.

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#6 2021-11-24 16:11:46

V1del
Forum Moderator
Registered: 2012-10-16
Posts: 14,469

Re: Latency spikes while gaming on a Broadcom wifi card

sudo journalctl -f follows everything happening in the journal from moment of invocation. Other filtering options are detailed in:

Last edited by V1del (2021-11-24 16:12:15)

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#7 2021-11-24 16:16:10

Vermoot
Member
Registered: 2021-11-17
Posts: 5

Re: Latency spikes while gaming on a Broadcom wifi card

There's very little happening in there. In fact the only thing I can see is this:

Nov 24 17:13:19 ArchMoot dbus-daemon[893]: [session uid=1000 pid=893] Activating service name='org.gnome.ScreenSaver' requested by ':1.132' (uid=1000 pid=39225 comm="/home/vermoot/.local/share/Steam/ubuntu12_32/steam")
Nov 24 17:13:19 ArchMoot dbus-daemon[893]: [session uid=1000 pid=893] Successfully activated service 'org.gnome.ScreenSaver'

Over and over again, every 20 seconds or so. I wonder what that is, but it doesn't seem related, other than seeing steam in there. Btw I'm not on gnome. I do have it installed, but I'm in an xmonad session.

There doesn't seem to be anything coinciding with the lag spikes I'm experiencing.

Last edited by Vermoot (2021-11-24 16:17:23)

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#8 2021-11-24 16:23:42

V1del
Forum Moderator
Registered: 2012-10-16
Posts: 14,469

Re: Latency spikes while gaming on a Broadcom wifi card

Did you run it with root/as sudo? Depending on your config you wouldn't see system level messages.if you don't get any messages then it's likely not something generic. And then likely something more inherent to the module/ general system setup. Somewhat hard to give general advice here, there are a lot of networking tweaks you can do on the kernel level, e.g. https://wiki.archlinux.org/title/Sysctl … erformance and https://wiki.archlinux.org/title/Networ … eue_length

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#9 2021-11-24 16:47:12

Vermoot
Member
Registered: 2021-11-17
Posts: 5

Re: Latency spikes while gaming on a Broadcom wifi card

I did run it as sudo. I initially get more unrelated stuff, or more even when I use sudo, stuff like that. Not the constant stream of stuff I expected, however.

I'll take a look at those links, thanks.

For an easier time speaking of this I'm on Discord or IRC, should you want to continue this.

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