TPS degradation

[Shevron]

Good morning,

I have a question about tps rates on the server (ticks per second). I'm the admin of a server that we run between a few friends. FTB Unleashed, Linux server hosted by verygames[dot]co[dot]uk and although it's a 16 player server, the active player count is 3-5.

Server works fine and all, with healthy tps of 20 most of the time. I'm noticing however that this degrades over time, to a point where if I don't restart the MC server for 24 hours, tps degrades considerably in the overworld. After a few hours running it's 18, then 15, and yesterday even dropped to 5, which is of course unplayable! Not even the day/night cycle works at that rate.

I have discussed this with the other players, and while we are all pretty advanced in our technologies - full blown IC2 UU-Matter production, complex bee breeding automation and all that, I have made sure that while offline, nobody is leaving on any machinery. All fabricators, extruders, quarries etc are being turned off before the player logs off, and we are pretty sure that we have no buildcraft pipes spitting out stuff and therefore lagging things out. There's maybe 3-4 chunkloaders in all, and no Mystrcraft dimensions. Just dimension 0 (overworld) and -1 (the nether) with -1 always keeping the healthy 20tps.

Case in point, I left the server running at a normal 20tps yesterday night, and logged in this morning to find it at 11tps, and incredibly laggy. Checked the logs, and nobody had logged in overnight, so the degradation happened on its own. Checked with the host support team, and they confirmed that ram and cpu never go over 50% usage, so it's not like we're overburdening the server.

A simple server restart brings everything back to normal, til it starts degrading again in a few hours.

Any ideas what might be causing this, or are there any tools that can help me isolate the problem?

Thank you

 

[Zarkov]

Install and use the Opis mod, which is a server profiling tool. Note: it replaces the mod Map Writer, so remove that if you have it installed.

 

[Shevron]

Thanks.

I'm using out of the box FTB Unleashed with only Jammy Furniture added. I'll check out Opis and see if map writer is lurking.

 

[lenscas]

Install and use the Opis mod, which is a server profiling tool. Note: it replaces the mod Map Writer, so remove that if you have it installed.

I believe that opis is for 1.6 not 1.5 what unleashed is.

Only help that I can give now is to say that it probely is a memory leak.

 

[rhn]

I believe that opis is for 1.6 not 1.5 what unleashed is.

Only help that I can give now is to say that it probely is a memory leak.

Yeah theres no 1.5 version of Opis(sadly).

 

[Shevron]

Darn it. I was seeing Dire's Opis spotlight and was already getting excited.

Oh well I'll keep restarting every so often then until we do the jump to 1.6.

Everyone is refusing to have me go 1.6 until Extra Bees and Equivalent Exchange make a 1.6 appearance

 

[Adonis0]

Darn it. I was seeing Dire's Opis spotlight and was already getting excited.

Oh well I'll keep restarting every so often then until we do the jump to 1.6.

Everyone is refusing to have me go 1.6 until Extra Bees and Equivalent Exchange make a 1.6 appearance

I thought Extra bees is in 1.6.x, it's just renamed. The mod that the previous extra bee machines is called Binnie's core

So I presume Binnie now has a set of mods

 

[Shevron]

I did have a search though NEI though, and I can't find any of the bees that extra bees adds, so I'm guessing it's not there yet.

Dunno maybe I'm just being thick and missing the whole thing.

 

[Adonis0]

I did have a search though NEI though, and I can't find any of the bees that extra bees adds, so I'm guessing it's not there yet.

Dunno maybe I'm just being thick and missing the whole thing.

The only bees that show up for me in NEI are the mundane ones (from hives in the wild) No mutations show up for me at all..

 

[Omicron]

Opis is nice, but not a panacea solution either. Basically, there are 4-5 core areas where performance degradation can occur, and Opis shows you one of them. It shows it incredibly well, but for example on my server it turned out that the source of lag I was investigating was elsewhere entirely and Opis couldn't show it.

Shevron, what you need is a JVM profiler. I personally used JVisualVM because it's relatively easy to use, but keep in mind that I'm running my server on my own Windows machine. If you're on a paid hosting service, you won't be able to just install a piece of software, and it will probably be running on Linux.

 

[Shevron]

Yeah it's running Linux, and I don't have direct access to the console anyways.

I'll just ride this through, and keep rebooting it. We'll be on 1.6 in a few weeks anyways, so it's not worth the trouble at this point.

 

[CovertJaguar]

If performance degrades over time, its likely a memory leak, the primary memory leak in MC is world leaks, things that hold onto world objects long after they are dead and gone. But it just as easily be something else too. Pretty much the only way to find a memory leak is to do a core dump, and I don't know if VisualVM can do that.

And yes, I also want to stress to all users that Opis only covers ONE of the possible causes of tps lag, and its not even worse one. Entities are 10x worse than the average Tile Entity (the only thing Opis monitors). Block updates are also a major issue. There are also tick handlers as well, and some mods put of a lot of stuff in tick handlers. Its even technically possible to move all Tile Entity updates (the only thing Opis monitors) to a tick handler in such a way that they would no longer appear in Opis. So please, take it with a grain of salt and realize that what Opis is showing you, is probably not causing your TPS lag.

 

[Shevron]

Thank you all for your very detailed feedback.