Network Performance System

Network Performance System

A general networking overhaul. What if it felt like singleplayer for everyone?

Network Performance System is a general networking overhaul, designed to tackle the problem created by high ping.

In Valheim, most objects are simulated by users. So a single high ping user in an area can make everything or all sorts of things feel terrible. This mod aims to address that in a number of ways.

Why this is different from the other networking mods

Every other Valheim networking mod treats multiplayer performance as a bandwidth problem — compression, bigger buffers, higher send rates, filtered broadcasts. That is the right diagnosis for ten people in one base saturating a shared cap. It does not handle a larger distributed server, or multiple players from vastly different geographic locations.

NPS addresses these issues in a number of ways:

• []Each peer gets their own round trip timing (RTT), healthcheck and bandwidth estimates

  []This allows dynamic adjustments to route around a poor connection[/]

  []Higher ping players with decent bandwidth allow the server to send more aggressively to these players in compensation[/]

  []Object ownership can be dynamically adjusted around players with poor connections to provide the best experience for all players in the area[/]

[]Objects which need network calls to interact with get ownership transferred ahead of time, making delay scenarios much less likely[/]

[]Objects that change ownership during active requests get their requests properly re-targeted against the new owner, and an item that still cannot be delivered is dropped at the station instead of lost[/]

[]Objects which are locally important (footsteps for example) are only network broadcast locally, instead of globally around the server[/]

[]Server garbage collection churn is significantly reduced compared to vanilla[/]

Installing

Server-only works. Vanilla clients get the send window, ownership, scheduler, station-request and creature-hit fixes with nothing installed on their end, and the server follows where they actually are rather than where they were two seconds ago. The server also sends settled or distant creatures to each player less often.

Installing on clients too adds latency compensation, live position reporting and the clean exit from a dead session for those clients, and lets a ship they own pass to whoever takes its helm. Creatures they simulate stop re-sending themselves while standing still, which matters most next to a pen of tamed animals.

Mixed groups are fine — benefits are per-player, and a client without the mod behaves exactly as vanilla. There is no version lock: nobody gets kicked for not having it.

Works on dedicated servers and on player-hosted games.

Requires BepInEx and Jotunn.

Diagnosing and reporting a problem

An easy way to start is the nps_stats display. Run nps_stats_collect (needs devcommands, since sampling costs a Steam call per peer per tick), play, then nps_stats.

A player the link-pressure table marks as LOSSY is already being dealt with: the server steps that one player's send rate down until their connection stops losing packets, and back up once it is clean, without changing anyone else's rate (Steam Transport / Enable Loss Backoff). A player whose loss does not improve - once their rate is below what their connection was already carrying, or at the lowest rate - has a connection problem the rate cannot fix: they go back to full speed and are left there until the server restarts. Loss measured during an outage at the server's end is ignored. The "Loss backoff" block shows who is backed off and by how much.

Lag, rubber-banding, hits not landing? Send a report.

Server owners: in BepInEx/config/MidnightsFX. NetworkPerformanceSystem.cfg, set Enable Network Monitoring = true in the Monitoring section. You do not need to restart, and an admin can also change it in game. Play through the problem, set it back to false, and zip the newest folder in BepInEx/NpsMonitoring/[