Tab list ping spikes whenever someone joins, gets sorted, or have their tab status changed.

[mibby]

I noticed the BungeeTabList ping display spikes from a stable number up to a high count (300+) for a second whenever someone joins the server, gets sorted, or have their name changed such as if going afk or no longer afk.

Is there any way to prevent the ping from spiking or is it all tied to the same update thread?

[CodeCrafter47]

The ping is not determined by BungeeTabListPlus itself, but by the (spigot) server. BungeeTabListPlus only displays the ping.

[mibby]

So then the ping spiking on the display would be the server thread itself being blocked by other plugins / permission calls when players login / need re-sorting?

[CodeCrafter47]

The ping packets are handled on the players event loop (netty), not on the games main thread, so they ping is not affected if a plugin blocks the main thread for an extended period of time. However it is affected by async events being delayed, and also by high CPU loads in general.

[mibby]

Hmm. So could routine java garbage collections be causing the spikes? I'm not sure what async events would be delayed consistently.

According to my node, the machine CPU usage never goes above 10% at the maximum.

[CodeCrafter47]

Garbage collections pause the entire application for a short period of time so they can be the cause of this effect.

[mibby]

I use an optimized set of garbage collection start-up arguments by @Aikar on java 8, so if that truly is the cause of the random ping spikes, that's a bit disheartening. :(

"{JAVA}" -server -Xmx10240M -Xms10240M -Dfile.encoding=UTF-8 -XX:MaxGCPauseMillis=100 -XX:+UseG1GC -DIReallyKnowWhatIAmDoingISwear=1 -XX:TargetSurvivorRatio=90 -XX:+UnlockExperimentalVMOptions -XX:G1NewSizePercent=50 -XX:G1MaxNewSizePercent=80 -XX:InitiatingHeapOccupancyPercent=10 -XX:G1MixedGCLiveThresholdPercent=50 -XX:+AggressiveOpts -XX:+AlwaysPreTouch -XX:+DisableExplicitGC -Djline.terminal=jline.UnsupportedTerminal -jar "{JAR}"

Generally in-game TPS is stable around 20 with hardly any drops below 19.9x.

[CodeCrafter47]

I'm not saying it is the cause, I just said that GC can cause this effect. Also keep in mind that the ping packet and its processing can be delayed anywhere along the road.

[mibby]

Is the ping packet tied to all users, not individual packets for each user? As when the tab list display changes due to a player login or afk status change, the ping display seems to spike for everyone for that second.

[CodeCrafter47]

Ping packets are sent out to players periodically by the spigot servers. A ping packet is always tied to a specific connection.