Problem FTB Direwolf 20 1.6.4 Server Lag

Skullywag

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Jul 29, 2019
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youre getting tick rate lag but Opis doesnt show anything? that seems...odd. Opis doesnt profile a few things that can cause lag mobs being one, try running a kill-all command (butcher if you have it) see if its a mobs pathing stuck, it happens sometimes in MCPC+.
 

Connor Gavitt

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Jul 29, 2019
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What is going on during that 15 second drop, what's in console. Things just don't pause for a few seconds without cause.
 

Francis Baster

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Jul 29, 2019
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I recommend getting this: http://nallar.me/buildservice/job/T...cessfulBuild/artifact/target/TickProfiler.jar

You may have to go into the config for it and turn the permissions part off (or you could just run the profile command on the console).

Once placed in your mods dir, fire up your server, stop server, change config where required, start server up again.

Wait for the hi CPU event to occur, then do (from the console): profile e

It might take a little longer to do its job during the event, but it will happen, then you just look for the things that are taking an excessively large amount of time to do stuff.

Other option is WarmRoast by sk89q (the worldedit guy), which is a seperate jar that runs independent of the game, assuming you have the MCP mappings for 1.6.4 you can use that to also give you an idea of where the issue might be.
Hadn't heard of WarmRoast before, looks very useful for the deobfuscation features thanks.
 
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Francis Baster

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Jul 29, 2019
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The messages I am getting in console... (Auto-saving not enabled) The server tick is going slow. The last tick was (something around 21000ms, sometimes more). I'm using MCPC+,
If you are getting a lag spike with a 21000ms tick time, then the program execution is most likely getting held up in some method. CPU profiling may tell which method it is, so I wouldn't be so fast to dismiss it.

I see you mentioned that auto save is turned off. Have you checked if this problem persists when autosave is turned on with regular /save-all commands, say every 10 minutes? I've seen lag spikes occur as a result of massive write queues building up in memory due to map saving being disabled. This occurred in spite of the fact that Java still had plenty of spare heap space available.
 
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Francis Baster

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Kinluki

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Jul 29, 2019
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Maybe a weird one, but one of the things which can give a terrible lag in 1.6.x servers are zombies. This is a known vanilla bug. It has to do with their ai and trying to calculate a path to someone if they can't reach it (be it a player or a villager). Don't know if it is the issue here, but who knows..
 

Sphinx2k

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Jul 29, 2019
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I like to add myself to the list of people with this problem.
Only thing i found in the forgeModloader.log file is this part:
Code:
2014-01-02 09:16:55 [INFO] [STDERR] java.util.ConcurrentModificationException
2014-01-02 09:16:55 [INFO] [STDERR]    at java.util.HashMap$HashIterator.nextEntry(Unknown Source)
2014-01-02 09:16:55 [INFO] [STDERR]    at java.util.HashMap$ValueIterator.next(Unknown Source)
2014-01-02 09:16:55 [INFO] [STDERR]    at net.minecraft.nbt.NBTTagCompound.func_74734_a(SourceFile:25)
2014-01-02 09:16:55 [INFO] [STDERR]    at net.minecraft.nbt.NBTBase.func_74731_a(SourceFile:119)
2014-01-02 09:16:55 [INFO] [STDERR]    at net.minecraft.nbt.CompressedStreamTools.func_74800_a(CompressedStreamTools.java:140)
2014-01-02 09:16:55 [INFO] [STDERR]    at net.minecraft.world.chunk.storage.AnvilChunkLoader.func_75821_a(AnvilChunkLoader.java:198)
2014-01-02 09:16:55 [INFO] [STDERR]    at net.minecraft.world.chunk.storage.AnvilChunkLoader.func_75814_c(AnvilChunkLoader.java:184)
2014-01-02 09:16:55 [INFO] [STDERR]    at net.minecraft.world.storage.ThreadedFileIOBase.func_75736_b(SourceFile:30)
2014-01-02 09:16:55 [INFO] [STDERR]    at net.minecraft.world.storage.ThreadedFileIOBase.run(SourceFile:23)
2014-01-02 09:16:55 [INFO] [STDERR]    at java.lang.Thread.run(Unknown Source)
2014-01-02 09:17:23 [INFO] [STDERR] java.util.ConcurrentModificationException
2014-01-02 09:17:23 [INFO] [STDERR]    at java.util.HashMap$HashIterator.nextEntry(Unknown Source)
2014-01-02 09:17:23 [INFO] [STDERR]    at java.util.HashMap$ValueIterator.next(Unknown Source)
2014-01-02 09:17:23 [INFO] [STDERR]    at net.minecraft.nbt.NBTTagCompound.func_74734_a(SourceFile:25)
2014-01-02 09:17:23 [INFO] [STDERR]    at net.minecraft.nbt.NBTBase.func_74731_a(SourceFile:119)
2014-01-02 09:17:23 [INFO] [STDERR]    at net.minecraft.nbt.CompressedStreamTools.func_74800_a(CompressedStreamTools.java:140)
2014-01-02 09:17:23 [INFO] [STDERR]    at net.minecraft.world.chunk.storage.AnvilChunkLoader.func_75821_a(AnvilChunkLoader.java:198)
2014-01-02 09:17:23 [INFO] [STDERR]    at net.minecraft.world.chunk.storage.AnvilChunkLoader.func_75814_c(AnvilChunkLoader.java:184)
2014-01-02 09:17:23 [INFO] [STDERR]    at net.minecraft.world.storage.ThreadedFileIOBase.func_75736_b(SourceFile:30)
2014-01-02 09:17:23 [INFO] [STDERR]    at net.minecraft.world.storage.ThreadedFileIOBase.run(SourceFile:23)
2014-01-02 09:17:23 [INFO] [STDERR]    at java.lang.Thread.run(Unknown Source)
2014-01-02 09:17:52 [INFO] [STDERR] java.util.ConcurrentModificationException
2014-01-02 09:17:52 [INFO] [STDERR]    at java.util.HashMap$HashIterator.nextEntry(Unknown Source)
2014-01-02 09:17:52 [INFO] [STDERR]    at java.util.HashMap$ValueIterator.next(Unknown Source)
2014-01-02 09:17:52 [INFO] [STDERR]    at net.minecraft.nbt.NBTTagCompound.func_74734_a(SourceFile:25)
2014-01-02 09:17:52 [INFO] [STDERR]    at net.minecraft.nbt.NBTBase.func_74731_a(SourceFile:119)
2014-01-02 09:17:52 [INFO] [STDERR]    at net.minecraft.nbt.CompressedStreamTools.func_74800_a(CompressedStreamTools.java:140)
2014-01-02 09:17:52 [INFO] [STDERR]    at net.minecraft.world.chunk.storage.AnvilChunkLoader.func_75821_a(AnvilChunkLoader.java:198)
2014-01-02 09:17:52 [INFO] [STDERR]    at net.minecraft.world.chunk.storage.AnvilChunkLoader.func_75814_c(AnvilChunkLoader.java:184)
2014-01-02 09:17:52 [INFO] [STDERR]    at net.minecraft.world.storage.ThreadedFileIOBase.func_75736_b(SourceFile:30)
2014-01-02 09:17:52 [INFO] [STDERR]    at net.minecraft.world.storage.ThreadedFileIOBase.run(SourceFile:23)
2014-01-02 09:17:52 [INFO] [STDERR]    at java.lang.Thread.run(Unknown Source)
2014-01-02 09:19:12 [INFO] [STDERR] java.util.ConcurrentModificationException
2014-01-02 09:19:12 [INFO] [STDERR]    at java.util.HashMap$HashIterator.nextEntry(Unknown Source)
2014-01-02 09:19:12 [INFO] [STDERR]    at java.util.HashMap$ValueIterator.next(Unknown Source)
2014-01-02 09:19:12 [INFO] [STDERR]    at net.minecraft.nbt.NBTTagCompound.func_74734_a(SourceFile:25)
2014-01-02 09:19:12 [INFO] [STDERR]    at net.minecraft.nbt.NBTBase.func_74731_a(SourceFile:119)
2014-01-02 09:19:12 [INFO] [STDERR]    at net.minecraft.nbt.CompressedStreamTools.func_74800_a(CompressedStreamTools.java:140)
2014-01-02 09:19:12 [INFO] [STDERR]    at net.minecraft.world.chunk.storage.AnvilChunkLoader.func_75821_a(AnvilChunkLoader.java:198)
2014-01-02 09:19:12 [INFO] [STDERR]    at net.minecraft.world.chunk.storage.AnvilChunkLoader.func_75814_c(AnvilChunkLoader.java:184)
2014-01-02 09:19:12 [INFO] [STDERR]    at net.minecraft.world.storage.ThreadedFileIOBase.func_75736_b(SourceFile:30)
2014-01-02 09:19:12 [INFO] [STDERR]    at net.minecraft.world.storage.ThreadedFileIOBase.run(SourceFile:23)
2014-01-02 09:19:12 [INFO] [STDERR]    at java.lang.Thread.run(Unknown Source)
The Server we own is running normal for over a year with 1.4.6 and 1.5 packs (with full members on the server tick time of 37ms). Now with the Direwolf20 1.6 Pack it is lagging like crazy when more people are online.
Now on the Server -> If i'am the only person on the server the tick time is around 19ms. With 2 it goes up to around ~40ms with spikes over 50ms. With 3 we are at 50 to 60ms with spikes to 70ms. 4 or more the spikes hit sometimes 150ms per tick.
It seems every player adds around ~20ms of tick time.

Last weekend i tried to find the cause of this.
I made a local copy of the server from the online host to my machine. Better tick rate on my machine then the host around 18ms. then without doing anything spike to around ~40ms.
OK created a fresh map -> 15ms with spikes to ~30ms.
Removed mod by mod and created fresh maps every time. the tick rate dropped as i removed more and more mods. Spikes happen every 2 minutes (arround 2 - 3 Times the normal tick rate). Then with every mod removed (only forge remained) ~4ms spikes to 9ms.

Opis did not show anything an our Server (fresh map has not much to show). The CPU during times of lag is at 100%, RAM is OK all the time.

So to round it up, i could not find the one mod doing this. Then i thought maybe to mob AI is causing this. Set the Server to peaceful tick rate and spikes don't change much.
I have absolutly no idea what i can do to make it more playable when more people are online at the same time. Hopefully someone can find an answer.
 

Francis Baster

New Member
Jul 29, 2019
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If this is happening on your server with no mods installed, can you try running some CPU or memory sampling to see what might be causing the issue? Tools such as JVisualVM or WarmRoast could help.

If the problem exists with just plain Forge then hopefully it will be fixed with their next version. But we need to make sure that the Forge devs are aware of this issue.
 

blood

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Jul 29, 2019
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The lag during world saves deals with how Mojang added new structure data for compatibility with 1.7 world updates. Basically, world generation logic has changed in 1.7 and in order to make sure 1.6 worlds can update to 1.7, Mojang had to save additional info to structures. However, one type of structure 'Mineshaft' is very common and as a result grows quite rapidly leading to performance issues during world saves. Unfortunately, there is no patch in forge to compensate for the issue at this time but if you really need this working on a forge server you can contact me in mcpc irc channel for a forge patch. If you are using MCPC+, we have already patched this in builds 188+ and will only require that you run StructureSaver plugin before updating to 1.7 to regenerate all your structure data. EvilSeph has made a good explaination here about the problem for those on MCPC+
https://forums.bukkit.org/threads/psa-minecraft-1-7-update-possibly-losing-structures.186617/

Hope this helps =)
 
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Sphinx2k

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Jul 29, 2019
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Hmm i don't know if this is the cause of the problem.Some more thinks i found out:
The Server logs shows a
Can't keep up! Did the system time change, or is the server overloaded?
Message exactly every 20 seconds in the log.
I checked with /forge tps the tickrate.
All summed up get me around 60ms but the overall line shows 80ms. So 20ms from nowhere? Opis shows only entitys and such things and is far from the 60ms if i sum this up.
And if one player is in the deep dark, this dimension has a tick time of ~20ms alone without any tech stuff. (Setting server to peacefull doesn't change anything)

Really frustrating.
 

MKellerBR

New Member
Jul 29, 2019
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Probably, in my case, the problem is the fact that the server uses shared resources on the Host, with other servers!
Apparently the problem occurs when another server, or more than one, performs backups or forced bailouts of the worlds loaded and can be raised when one or more servers that share the same Physical Server Host, reboot the same time, because these moments there is a great CPU and IO HD.
I noticed that in hosted Hosts SSD servers with this problem does not occur!
 

MKellerBR

New Member
Jul 29, 2019
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I using other host now... and works fine, without the error!!
The problem is in the host! Disk IO or CPU overloaded!
 

Curatho

New Member
Jul 29, 2019
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so i play only whit a friend of my so we are whit 2 people. and it gives lag spikes.. some times only when running.. so its just randering to mutch ?? or do i need to get more ram for the surver?? useing serverstart.bat whit
java -Xms2048m -Xmx2048m -XX:permSize=128m -jar FTBServer-1.6.4-965.jar nogui
pause