250-330ms round-trip latency on a fully wired setup.

[AUScythe]

I'm getting fairly bad results when trying to use an RPI 3B+ to replace my steam link, which was destroyed by lightning a few years back.

I'm seeing 250-330ms latency between a button press and screen action, as measured with a 240 fps camera. There are some links to the videos I've recorded at the bottom.

The on-screen stats look fine: https://imgur.com/a/ls49GN1

Anyone got any suggestions? I've done a fair bit of digging but I haven't found any of the usual solutions helpful.

RPI 3b+
Stress tested at 1.2GHz overclock, max temp of 75 degrees.
Heatsink on RAM/CPU,
Wired 100Mb/s ethernet network between PC and RPI - no wifi
No undervolt warnings.
Debian 9.13
Latest steamlink application.
256 MB VRAM reserved.
1360x768 resolution.
Stats overlays show no problems. Under 1ms input latency, 13-16ms display latency. Under 1ms ping time. 0% packet loss.
NVENC H264 capture with a RTX 2080.
Raspberry Pi hardware decoding,
Steam controller using USB dongle.
Also tried xbox one s bluetooth controller with no improvement.
Balanced video quality.
Automatic default settings.
RPI CPU at about 30% load when streaming.
No bumps on stat graph when streaming.
Nothing scary printed to console from the steamlink application.
Tried starting the steamlink app via a @reboot crontask and via an interactive terminal - same results.

https://youtu.be/9f54fSeGaC8
https://youtu.be/hHs8gKjSwXU
https://youtu.be/Mzd-YCWvsG4

[_I_]

its using steam internet relays

check windows network settings, make sure its set to private not public


the link will be delayed from the host by around 20ms (1 frame at 60hz 16ms)
since it needs to captures, compress, transmit, decompress, display
and sending controls back to the host

[AUScythe]

Originally posted by _I_:

its using steam internet relays

What makes you suggest that? It's configured to use direct mode, and the overlay reflects this. Just in case I did as you suggested and changed the host's ethernet network mode to private, from public, and tested again. The latency was unaffected. I then powered off my internet modem and the remote play stream was not interrupted.

I think my problems are elsewhere.

[_I_]

are you using wifi?
that can cause a little more lag

pingbomb the link and router while streaming
ping -t ip
hit ctrl+c to stop and show min/max/avg and loss

[AUScythe]

As I mention in my original post: No wifi, <1ms ping.

[AUScythe]

@Xenophobe All CAT5e via a 100Mb switch, to a gigabit switch, then to the PC running the game. I'll try upgrading the pi to debian 10 and see if that helps matters. Cheers.

I re-tested using a USB keyboard plugged into the PI navigating the steam big picture UI. In this setup I got 241ms of latency between keypress and the UI responding. This takes wireless controller and game latency out of the equation.

[AUScythe]

I have two monitors on the host PC. I changed the monitor used to display steam big picture in the host streaming settings and now the latency is down to 170ms. An improvement, but still room for improvement.

The network is fine. I ran the bandwidth test utility built into the steam link client and it only started dropping packets near 80Mb/s, which is pushing the limits of the ethernet interface on the RPI3B+

[_I_]

make sure both displays are plugged into the gpu not the mobo

[Xjph]

Looking at the stats image would indicate that everything is fine in the Steam Link app itself, and it's the final display step from the Pi and/or the monitor itself that's introducing delay.

You might want to try testing a different monitor on the Pi, or minimizing any scaling operations that need to take place (run the game, the steam link streaming resolution, the Pi's display resolution, and the native display resolution of your final output — if possible — all at exactly the same value).

[_I_]

is the host set to change the res to match the client?

and this should be in the pi subforum
https://steamcommunity.com/app/353380/discussions/6/