[0.13.13] [Multiplayer] Per-player FPS/UPS not useful

[thuejk]

I were recently part of a multiplayer Factorio speedrun attempt on AntiElitz's channel on twitch. We had some setup problems, because one of the players apparently had a too slow CPU, which would start lagging once 6 people were connected.

The problem/bug here was that the factorio debug output were not showing the offending user. The FPS/UPS info you get when you hit F5 showed all the players as dropping the same amount of frames. It was only through trial and error we found out the problem user, without whom everything worked fine (and he then said it must be his slow CPU).

Surely the problem user should be identifiable via the FPS/USP debug display?

The stream: https://www.twitch.tv/antielitz/v/81021950 (See for example 00:25:16)

[Loewchen]

I think there are a few misconceptions, just a few things to clear up:

1. the show_fps option only shows you YOUR fps/ups and is completely independent of other players
2. the CPU load is (almost) independent of the number of players
3. the lag shown in the video is network lag not performance lag, performance lag only shows by the game running at a slower speed constantly

[Rseding91]

Just wondering; who did it end up being? Because my guess is "si" since his wait-time on the debug info was always highest.

[daniel34]

Just wondering; who did it end up being? Because my guess is "si" since his wait-time on the debug info was always highest.

It ended up being Letaledosis100, after they started a new game without him (around 00:34:00) the wait-time stayed at 0 (or very close to it) for all of them.
The wait-time display is generally not that useful as it appears to be, most of the time all peers will have a value in the same range and the player causing the lag isn't necessarily the one with the highest wait-time.

It's sometimes hard to find the lagging player with the current pseudo-peer-to-peer implementation as they could have joined earlier when the game ran fine but as more peers join the game their connection can't handle the additional packets it receives from / sends to the new peers (rerouted by the host).
That was also the case with OP's game as Letaledosis100 joined as the 3rd player and it ran fine at that point, only as soon as 5-6 players were in the game it started to lag. In the new game afterwards (without him) they were 7 players with no problems.

With the multiplayer rewrite announced in FFF #147 this should be solved as the overall number of packets goes down from O(n^2) to O(n) and the network load per peer (packet count) doesn't increase with the number of players, only the size of the merged package does.

[Rseding91]

Anyway, all of this is changing for 0.14 with the MP code re-write so this will be solved with that.

[JCav]

So what's the current recommendation for trying to get more than 2 people to successfully play at once? A few friends and I tried to play .13.17 tonight and with 2 players, it was fine, but the moment the 3rd player started to join the upload speed (I was host) went to crap, and the game slowly stuttered into unresponsive hanging.

We tried rolling back to the stable release and thought things were going better for about 30 seconds, then it went to crap again.

No mods, and my CPU is a 4770k, with 16GB of RAM and 780Ti in SLI, so I know it wasn't a performance issue with the hosting PC.

[Rseding91]

So what's the current recommendation for trying to get more than 2 people to successfully play at once? A few friends and I tried to play .13.17 tonight and with 2 players, it was fine, but the moment the 3rd player started to join the upload speed (I was host) went to crap, and the game slowly stuttered into unresponsive hanging.

We tried rolling back to the stable release and thought things were going better for about 30 seconds, then it went to crap again.

No mods, and my CPU is a 4770k, with 16GB of RAM and 780Ti in SLI, so I know it wasn't a performance issue with the hosting PC.

That sounds like a standard "not fast enough internet" issue. What's your upload rate?

[JCav]

Generally it's around 12mbps



Thank you for taking the time to respond.

EDIT: Since you've taken the time to reply, I believe this is the log file from the incidents that we had tonight. Hopefully you find them helpful if you think there's something worth looking into. Thank you again.

[Loewchen]

This has been fixed with 0.14 already so ill move this to fixed.