"DoMobSpawning" is causing reduced tick speed, causing general tick lag

Yeah, I've noticed this.

oh, just remove the snapshot and add the snapshot back. It should be a bit slow but then come back to normal, but idk why this is happening

its the game ticks lagging... im not sure why this happens, i had to restart my adventure map because of it!

If it helps comment back, or try to figure out another way to fix it, but it seems fine for me when I removed the snapshot and added the snapshot back.

Ya it puts the animations like a really slow paper animation. Report back if it's fixed or not.

It is not fixed for me anymore. I went into another world and it broke. I hope Mojang sees this.

It fixes itself but sometimes it doesn't :/

I am restarting my world but it does not fix itself

Confirmed for 14w25b

What is "deleting the snapshot and adding it back"?

Yeah I noticed this too.

Also in snapshot 14w26b What the heck!? mojang fix this!!! also the heads are broken >:00000 What is mojang doing back there!?

@Aaron Stultz, they're rewriting whole minecraft to make it easy for modders to make their mods so we'll encounter a lot of bugs now.

heads fixed 14w26c. lag still here

Simplifying this ticket to the most prominent of the multiple bugs posted here. It is much easier for us to deal with bug reports when they contain only one bug. Feel free to create new ticket(s) with additional bugs.

Alright. BTW i don't feel like making a topic about this but when you hold some item it looks weird... Like it is not in your hand

That's MC-58037

(Moved from MC-57957)

The hurt and death animations are 2x slower than those in 1.7.10. It's just the speed of the animation: slower knock-back and slower falling-over death animation. It is more noticeable on hostile mobs.

Not game-breaking, but it is very anti-climatic and hurts immersion.

Video: http://www.twitch.tv/ezerarch/b/543899962?t=4m45s

Yes, only on certain worlds, though. I generate a world with the exact same seed as my LP, and the knockback/slimes is really floaty. Superflat seed that doesn't make the mobs floaty: 3;minecraft:bedrock,62*minecraft:stone,minecraft:grass;4;
New worlds that aren't hardcore seem to have this problem, plus most superflats.
I've also noticed the game doesn't save and the block-placing sounds are like 10-30 seconds delayed.

Same for me, minecraft snapshot 14w29b, in addition, at 14w29, open/close doors animation, place and remove blocks textures and chunks loading textures are very slow to update (like X-Ray).

@@unknown: This is MC-62166

I've been noticing this in 14w29b whenever I get over about 200 entities loaded. In 1.7.10 200 entities is like a day at the beach.

Everything moves so slowly like matrix.
(even frame per second shows around 60-70)

Setting the gamerule doMobSpawning to false removes a lot of the performance issues. Also, here is a video of the issue:
https://www.youtube.com/watch?v=kOxq3RhIOyw
The issue is strongest in open air worlds or a superflat world with the setting 3;minecraft:barrier;1;

Setting doMobSpawning to false stops all natural mob spawning, not everyone wants that.

I have noticed the more solid blocks are inside the bottom most chunk-sections of the loaded region, the less is the lag. So if the bottom 16 layers are filled with solid blocks the lag almost gone, if not completely. If they are empty the lag is the strongest. And if the bottom 6 layers are filled, the lag is somewhere between both.
Like "ShadowofElements" I also noticed that the lag is gone if the gamerule doMobSpawning is set to "false".
Also the lag does not only involve the laggyness of mobs but also the flowing speed of fluids and lots of other things. This is caused by the slow tick rate of the internal server. So I think the bug title is kind of inappropriate.

Tutorial to test the tick rate of your internal server:
You can test the tick rate by typing "/debug start", waiting a couple of seconds and then type "/debug stop". Now divide the displayed number of ticks by the number of seconds. If there is there is no lag, the value should be somewhere around 20 ticks/second. The lower the number is, the more lag you have.

Affects 14w31a.

I can confirm this from my Skyblock world. I've attached log messages, there is some garbage because I've set CompileTreshold to ridicilous values, so don't get distracted by that.

http://pastebin.com/ig9MD5vA

Most Entities Are Affected Including Items and Eye Of Enders.

Confirmed in 14w32a

Confirmed in 14w32b.

Is this happening for windows users and mac or is it just me

Same for me, new worlds created now are affected immediatly since 14w32a

Maybe it depends on the system because I for example have no tick lag.

Confirmed on 14w32d, Windows7

Doing some more testing, i've noticed that the cause of the lag is different depending on the type of world you have.
If the world is a flatmap, the cause of the lag is probably the tick "mobSpawner".

However, if the world is not a flatmap the lag is caused by either "ai", or "tickBlocks".

This is spammed in the console while doing a debug profile on a standard world (not a flatmap).

[14:28:37] [Server thread/WARN]: Something's taking too long! 'root.levels.world.tick.tickBlocks' took aprox 213.773935 ms
[14:28:37] [Server thread/WARN]: Something's taking too long! 'root.levels.world.tick' took aprox 288.520694 ms
[14:28:37] [Server thread/WARN]: Something's taking too long! 'root.levels.world' took aprox 294.233015 ms
[14:28:37] [Server thread/WARN]: Something's taking too long! 'root.levels' took aprox 295.818544 ms
[14:28:37] [Server thread/WARN]: Something's taking too long! 'root' took aprox 298.072367 ms

If the world is a flatmap,

[14:44:44] [Server thread/WARN]: Something's taking too long! 'root.levels.world.tick.mobSpawner' took aprox 307.398711 ms
[14:44:44] [Server thread/WARN]: Something's taking too long! 'root.levels.world.tick' took aprox 325.851728 ms
[14:44:44] [Server thread/WARN]: Something's taking too long! 'root.levels.world' took aprox 326.617546 ms
[14:44:44] [Server thread/WARN]: Something's taking too long! 'root.levels' took aprox 327.848397 ms
[14:44:44] [Server thread/WARN]: Something's taking too long! 'root' took aprox 330.947083 ms

The mobSpawner does not cause lag on a normal map at all. Only on a flatmap.

If a flatmap eventually gets some mobs on the map (via spawn eggs for example), it dosn't take a lot for the sever to start lagging because of "entities.regular.tick.ai"

[15:00:19] [Server thread/WARN]: Something's taking too long! 'root.levels.world.tick.entities.regular' took aprox 158.373306 ms
[15:00:19] [Server thread/WARN]: Something's taking too long! 'root.levels.world.tick.entities' took aprox 159.628794 ms
[15:00:19] [Server thread/WARN]: Something's taking too long! 'root.levels.world.tick' took aprox 188.109298 ms
[15:00:19] [Server thread/WARN]: Something's taking too long! 'root.levels.world' took aprox 194.34876 ms
[15:00:19] [Server thread/WARN]: Something's taking too long! 'root.levels' took aprox 229.786808 ms
[15:00:19] [Server thread/WARN]: Something's taking too long! 'root' took aprox 235.771681 ms

I could totally reproduce this in a quite obvious way in 14w32d:

Things you can do to test it are:

1. Create a superflat world with the following conditions:

   • Gamemode: creative (to make it easy for you)

   • Generate structures: off

   • World type: Superflat

   • Bonus chests: off

   • Use the following superflat presets: 3;minecraft:bedrock,minecraft:grass,3*minecraft:air,minecraft:grass,3*minecraft:air,minecraft:grass,3*minecraft:air,minecraft:grass,3*minecraft:air,minecraft:grass,3*minecraft:air,minecraft:grass,3*minecraft:air,minecraft:grass,3*minecraft:air,minecraft:grass,3*minecraft:air,minecraft:grass,3*minecraft:air,minecraft:grass,3*minecraft:air,minecraft:grass,3*minecraft:air,minecraft:grass,minecraft:grass,3*minecraft:air,minecraft:grass,3*minecraft:air,minecraft:grass,3*minecraft:air,minecraft:grass,3*minecraft:air,minecraft:grass,3*minecraft:air,minecraft:grass,3*minecraft:air,minecraft:grass,3*minecraft:air,minecraft:grass,3*minecraft:air,minecraft:grass,3*minecraft:air,minecraft:grass,3*minecraft:air,minecraft:grass,3*minecraft:air,minecraft:grass,3*minecraft:air,minecraft:grass,3*minecraft:air,minecraft:grass,3*minecraft:air,minecraft:grass,3*minecraft:air,minecraft:grass,3*minecraft:air,minecraft:grass,3*minecraft:air,minecraft:grass,3*minecraft:air,minecraft:grass,3*minecraft:air,minecraft:grass,3*minecraft:air,minecraft:grass,3*minecraft:air,minecraft:grass,3*minecraft:air,minecraft:grass,3*minecraft:air,minecraft:grass,3*minecraft:air,minecraft:grass,3*minecraft:air,minecraft:grass,3*minecraft:air;1; (This is not as strange as it looks. it will just be a lot of space for mobs to "possibly" spawn and move around in)

2. Load the world and do /gamerule doMobSpawning false

3. do /kill @e (Do this some times untill you see nothing getting killed/dissapear)

4. Let the world load fully around you

5. Create a redstone repeater loop with like 20 repeaters set to max delay.

6. Add a button to some block at the end and press it.

7. Allready here you will probably see a problem, but to continue do the following steps untill you can see some kind of improvement:

   • Lower the draw distance in small steps.

   • Let the world load around you.

   • Check for time running smooth again (your redstone clock)

   • If it doesnt, repeat..

8. When your clock goes around in a semi "ok" manner, put /gamerule doMobSpawning true and observe results.

Edit:

To see the results more clearly do the following after you have gotten to your "sweetspot" where time actually runs at all:

• set /gamerule doMobSpawning false

• kill off everything with some repeated /kill @e (you need to do this more than once to kill items aswell)

• write /deubg start and wait for 5 min or so..

• Write /debug stop. (Note down the values of time and ticks)

• do / /gamerule doMobSpawning true

• write /deubg start and wait for 5 min or so..

• Write /debug stop. (Note down the values of time and ticks)

devide ticks/seconds for each to get a tps.

See the differences.

I think I found the problem: it only "lags" with the gamerule doMobSpawning set to true. Try to set it to false and it should fix the problem 🙂 Worked for me!

Yes.. And if you set "/playMinecraft = false", your computer will not lag at all...

In my regular world (not superflat) there are areas where the tick length suddenly increases from around 30 ms to 250 or 300 ms, which dramatically slows down minecarts, etc. This didn't happen in the 1.7 versions, only in the 1.8 snapshots. I'm not sure in which snapshot it started happening. Changing doMobSpawning to false does fix the problem, but only for a while. Something then automatically changes doMobSpawning back to true.

I've noticed that once I encounter an area of my world that makes the tick length very long, that traveling back to areas nearby where the tick length was short does not fix the problem, meaning the tick length stays long. Maybe this is because the offending chunks are still loaded. If I go far enough away from the offending areas, the tick length drops back down to normal.

The increase in tick length never seems to be gradual. It always jumps suddenly from normal length to really long in the offending areas. Also, it doesn't seem to be related to fps or to the speed of the computer. Running the same world on a Macbook Air and a fast iMac has about the same really long tick length, despite the fps being about four times higher on the iMac.

I've investigated this issue a bit and was able to identify the culprit as the complex "mobSpawner" procedure.
The corresponding method is obfuscated as ara/a(qs, boolean, boolean, boolean) in the snapshot 14w33a.

In a superflat world, during a single invoke of that method, around 7000 instances of entities are created using reflection in the inner-most loop... per tick.

Inside this inner loop, after an Entity was created, a verification process follows, checking if that particular Entity is suitable for a randomly generated position.
If this verification process fails, the entity is dismissed and the inner-most loop continues to run far too "long".

I slightly modified this method by inserting an additional control-flow statement after a verification failure that jumps into one of the outer-loops that iterates the valid chunks.
This modification may not follow intended behavior, but significantly reduced the time spent on this method and stabilized the tick-rate back to normal.

Confirmed for 14w33a/b/c

Not only in Windows XP. I have Windows 7 64 bits and I have the same problem.

Please fix before 1.8 release! Lucas Mayrhofer did find the problem!

I have observed that this happens when you create a new world only. My previous worlds run fine with entity handling.

Looks like the mob spawning causes excessive load. With 14w33c on a superflat world render distance 10, during the day, I get:

20 Ticks per second with /gamerule doMobSpawning false
17,6 Ticks per second with /gamerule doMobSpawning true

These are technically two different issues

1) The knockback of hitting mobs is slower compared to 1.7.10 overall
2) Mobs are generally lagging out, moving very laggy etc.

@Tomaz Voros

holy **** thank you.

I got 2 ticks / sec with true and 20 ticks /sec with false!

You helped my alot 🙂

@[Mod] Galaxy_2Alex
The cause is the same in both cases. Reduced tick speed.

@Thijmen F
But... the solution is not acceptable for Survival worlds 😛

Confirmed in 14w34b.

It should also be mentioned that Dinnerbone said a pre-release could be planned for this week. I would rather not see this bug in a pre release.

Am not sure if this is the same problem, but I've noticed that any medium number of mobs in front of you causes FPS drop. In 1.7 I could use my skeleton farm and have 150 mobs in front of me and still get 25+ fps. Now, in the 1.8 snapshots (any of them), I find that once I get 30 or 40+, my FPS drops to low teens.

And that is just standing still in front of a mob farm. Getting up to 150 mobs my FPS drops into single digits. I have 3Gig allocated and am only using a fraction of it. If this is a different bug, I can open a ticket on it.

Confirmed in 14w34c.
The mob spawner creates and discards thousands of entities per tick in superflat worlds, causing the reduced tick-speed.

Confirmed 14w34d

I really hope this gets fixed in 1.8. Dinnerbone said 14w34d may be the last snapshot.

I too have this, specifically with a large redstone clock in my world (This happens even when it's off). Mac OS X 10.9.4, Latest Java.

I did short testing and it seems that this has been fixed in 1.8 pre1.

Same here. It seems fixed in 1.8-pre1. 🙂

I can also confirm.

Fixed in 1.8-pre1, but old worlds that had this bug still contain this bug. 🙂

It might go away after a while. Also, I won't close this just yet, just wait for some more reports that it's fixed.

@Manel Angresola Navarro i don't think it is bound to the world. It depends on the game version.

@Tomaž Vöröš After playing the world in the version before, I changed to pre-release, and it still lagged. It may be bound only from worlds that had this bug. Btw, haven't tried what @Galaxy_2Alex said, I just copy-pasted my work in another world 😛

For me the bug is also fixed, even in old worlds.

This should be one of the highest priority bugs in 1.8, as it causes a lot of lag for many maps and superflat worlds. A lot of players will complain about the new found lag in certain situations, so this bug should be fixed ASAP. Please help us, Mojang

Fix confirmed, even if worlds created in 14w25b .. 14w34d still having this issue. Those worlds should be deleted or replaced by pre-14w25b backups.

This is most definitely not fixed for me. Even when no clients are connected, my server has an average tick of around 140ms from the time I run it until it eventually closes itself from the lag. And this is with the view distance set down to 3 chunks on the server. This is the same performance (or lack thereof) I've had since 14w25b.

Opening the 1.7.10 server on the same computer and serving the same world has the server idling at 2ms ticks when no clients are connected and 35ms ticks when I do connect.

@@unknown: That world is broken.

Confirmed FIXED in 1.8-pre1 on a freshly created superflat world!
Also there seems to be less tick lag on other worlds as well!

So if a world is created in lets say, 14w30c, I will keep having this issue?

What exactly is stored in world data which makes them remain broken if created in 14w25b?

This has NOT been fixed. Tested on every old and new world I have created. Unless what I'm having is a separate issue, I can say that this is NOT fixed, according to Kumasasa saying what I'm having is this issue. Please test again. This was mine: MC-69655.

Cannot confirm in 1.8-pre3.
However, remember that doMobSpawing used to only affect superflat worlds. If there is any lag, it is probably caused by AI or slow chunk loading, etc

I suggest also making sure this affects worlds created in 1.7.10, not just worlds created in a snapshot.

Same problem on a server that never used any snapshot or mod...
Minecarts, Redstones, Mobs, Horses .... Everything is like ten times slower for everyone on the server 😞.
We walk faster than minecarts and horses.

And I never ever had so much "[Server thread/WARN]: Can't keep up! Did the system time change, or is the server overloaded? Running 3739ms behind, skipping 74 tick(s)" before oO

Is it completely necessary to force a crash? I mean, others are having this problem too... Still in the final release.

Same problem here too. Deleting the player files seems to fix the problem... at least in single player.

It did not solve the problem on our server to delete the player files.

In 1.7.10 we had no server problems like this, but when we updated today, the server gets up to 2-3 min behind sometimes.. We even had to change the server properties file to keep it from crashing all the time..
As it is now, it is unplayable...

I do not know if it is this bug that causes the delay on our server, but I can not see what else it would be...

There is still something causing severe tick lag on my world in the 1.8 pre-releases. (That world didn't have any tick lag in the 1.7 releases.) I can make the tick lag disappear temporarily by changing my render distance, but then if I activate one of my redstone devices with a clock, it starts getting slower and slower and eventually nearly stops. Then everything has tick lag, even if I turn off the redstone circuit that triggered the tick lag, until I change the render distance again, and the tick lag disappears again.

So should I open a new ticket about this or is it going to be opened up again?
This is still an issue on a survival world from 1.7.10 --> 1.8 official release. (Have not ever been opened in the snapshots)

Mobs get slow, tickspeed is slow and so on..

So... Confirmed in 1.8

If you have time to open a new ticket, short and complete, saying that we are several players saying on Jira that these news kind of lag are a real problem in multiplayer, it would be perfect.
Maybe quote some things we said, so that the moderator can understand it's not only you, and it's on world that made the direct 1.7.10 to 1.8 upgrade without using snapshots :/.

@@unknown: Yes, make a new ticket.
This ticket is about lag / delays introduced in 14w25b and not when upgrading worlds from 1.7.10 to 1.8.
Please attach there a 1.7.10 world showing the symptoms.

So.... What you are saying is that I should copy the whole description of this post, but instead of the part "This is only affected for me in this snapshot. (snapshot 14w25b)" I write "This happens in 1.8 in the same way as in 14w25b"?

Feels a bit stupid to report the exact same issue and just say that it affects 1.8 as the difference..

To be honest, I don't know if I can be bothered to report this again...
But if I do, it will probably after MCP is up so that I can make sure I know what is causing it and maybe even make a fix for it, since I don't think that a report like "I experience slow mobs and slow tickspeed, please fix" will give any results at all here..

Again: This ticket is about lagging in worlds loaded/created in versions 14w25 ... 14w34 and was fixed in 1.8-pre1.
Lagging in 1.7 or older worlds in 1.8 is a different issue.

But I made new worlds in 1.8, and they have the problem still. It's not just old worlds. Minecart riding is pretty laggy too.

@unknown: You might see MC-62166 or MC-45458 but you failed up to date to provide a crash report and a sample world.

I don't get what you are saying. I will say this again, it is not just on 1.7 worlds.

But after playing awhile in survival I've experienced this: Mobs jump and get knocked back slowly. If there are lots of mobs around, the game will slow down, then quickly speed up again to where the mobs are, which can cause a swift death. I've seen this in new worlds too. And, sample world? Create a new world, it's on any. And in that world, punch a mob, it will go back slowly. Tested on NEW 1.8 WORLDS. If you say this is not caused by this issue, it MUST be a different one. And if that is the case, reopen my ticket.

This bug is extremely annoying and makes fighting mobs at night a lot more dangerous and tedious then it is supposed to be. I used to go outside at night when playing survival, and fight mobs in a smooth, on-your-heels fashion. Now that is no longer the case, as this, combined with the mobs not seeing the player immediately bug and entities turning invisible, makes fighting at night annoying, to say the least. If you really want me to, I can post a crash report from a new world. But I don't see how that would help that much, considering you can see it.

@@unknown: Then finally attach an affected world here

Here it is, sorry for lateness. It is related to either this report or MC-69655 as stated above. I am still having this problem on all new worlds I create, from the moment I create it. This is why I believe it is a mob related issue instead of this one, but you can decide that. Either way something is still occuring in the game.

Minecraft Crash Report ----
// I just don't know what went wrong 😞

Time: 10/8/14 10:55 PM
Description: Manually triggered debug crash

java.lang.Throwable
at bsu.r(SourceFile:1563)
at bsu.as(SourceFile:877)
at bsu.a(SourceFile:314)
at net.minecraft.client.main.Main.main(SourceFile:120)

A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

– Head –
Stacktrace:
at cen.a(SourceFile:308)

– Affected level –
Details:
Level name: MpServer
All players: 1 total; [cio['Brickmaster125'/302, l='MpServer', x=86.31, y=84.87, z=630.85]]
Chunk stats: MultiplayerChunkCache: 49, 49
Level seed: 0
Level generator: ID 00 - default, ver 1. Features enabled: false
Level generator options:
Level spawn location: 84.00,64.00,256.00 - World: (84,64,256), Chunk: (at 4,4,0 in 5,16; contains blocks 80,0,256 to 95,255,271), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
Level time: 6867 game time, 6867 day time
Level dimension: 0
Level storage version: 0x00000 - Unknown?
Level weather: Rain time: 0 (now: false), thunder time: 0 (now: false)
Level game mode: Game mode: creative (ID 1). Hardcore: false. Cheats: false
Forced entities: 40 total; [acb['Rabbit'/12870, l='MpServer', x=141.34, y=85.00, z=661.34], acb['Rabbit'/12869, l='MpServer', x=131.34, y=80.00, z=669.50], acb['Rabbit'/12868, l='MpServer', x=140.69, y=86.00, z=661.00], adw['item.tile.flower1.dandelion'/13147, l='MpServer', x=36.66, y=29.00, z=659.16], afy['Slime'/15301, l='MpServer', x=90.69, y=77.02, z=619.94], afy['Slime'/15302, l='MpServer', x=96.19, y=77.17, z=626.49], acb['Rabbit'/12886, l='MpServer', x=138.53, y=101.00, z=624.53], abr['Chicken'/12884, l='MpServer', x=131.31, y=99.00, z=617.50], abr['Chicken'/12885, l='MpServer', x=139.63, y=103.00, z=636.41], xk['Experience Orb'/15047, l='MpServer', x=102.22, y=90.00, z=618.91], xk['Experience Orb'/12165, l='MpServer', x=81.59, y=74.00, z=605.75], abr['Chicken'/8769, l='MpServer', x=110.44, y=79.00, z=645.31], aca['Pig'/8774, l='MpServer', x=100.53, y=76.00, z=631.59], aca['Pig'/8772, l='MpServer', x=91.09, y=78.00, z=630.00], agp['Villager'/10491, l='MpServer', x=52.47, y=64.00, z=603.91], aca['Pig'/8773, l='MpServer', x=95.81, y=77.00, z=623.13], agp['Villager'/10487, l='MpServer', x=89.21, y=78.00, z=649.55], acb['Rabbit'/8171, l='MpServer', x=64.31, y=64.00, z=602.53], acb['Rabbit'/8172, l='MpServer', x=54.75, y=71.00, z=612.81], xk['Experience Orb'/12916, l='MpServer', x=73.41, y=69.00, z=602.03], adw['item.item.feather'/13571, l='MpServer', x=85.38, y=79.00, z=638.81], cio['Brickmaster125'/302, l='MpServer', x=86.31, y=84.87, z=630.85], abr['Chicken'/8767, l='MpServer', x=90.09, y=78.00, z=629.44], agj['Zombie'/16352, l='MpServer', x=108.50, y=39.00, z=576.50], agj['Zombie'/16353, l='MpServer', x=108.50, y=39.00, z=577.50], acb['Rabbit'/14476, l='MpServer', x=87.59, y=86.01, z=675.09], acb['Rabbit'/12860, l='MpServer', x=140.19, y=100.00, z=619.28], abr['Chicken'/12861, l='MpServer', x=132.25, y=101.00, z=623.53], abr['Chicken'/12859, l='MpServer', x=128.63, y=99.00, z=613.56], adw['item.item.porkchopRaw'/12993, l='MpServer', x=99.38, y=73.00, z=635.09], acb['Rabbit'/14258, l='MpServer', x=119.09, y=78.00, z=668.47], afy['Slime'/16426, l='MpServer', x=85.84, y=79.00, z=631.44], afy['Slime'/16427, l='MpServer', x=94.91, y=77.47, z=634.22], xk['Experience Orb'/13030, l='MpServer', x=98.59, y=73.00, z=633.44], afy['Slime'/16425, l='MpServer', x=84.84, y=80.09, z=634.94], agj['Zombie'/14425, l='MpServer', x=91.50, y=42.00, z=672.50], xk['Experience Orb'/13031, l='MpServer', x=102.47, y=72.00, z=636.13], acb['Rabbit'/11900, l='MpServer', x=101.44, y=78.00, z=669.44], adw['item.item.slimeball'/16476, l='MpServer', x=82.75, y=80.00, z=632.53], abr['Chicken'/12434, l='MpServer', x=77.41, y=87.75, z=648.50]]
Retry entities: 0 total; []
Server brand: vanilla
Server type: Integrated singleplayer server
Stacktrace:
at cen.a(SourceFile:308)
at bsu.b(SourceFile:2252)
at bsu.a(SourceFile:323)
at net.minecraft.client.main.Main.main(SourceFile:120)

– System Details –
Details:
Minecraft Version: 1.8
Operating System: Windows 7 (x86) version 6.1
Java Version: 1.7.0_67, Oracle Corporation
Java VM Version: Java HotSpot(TM) Client VM (mixed mode), Oracle Corporation
Memory: 216015536 bytes (206 MB) / 372084736 bytes (354 MB) up to 523501568 bytes (499 MB)
JVM Flags: 6 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx512M -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalMode -XX:-UseAdaptiveSizePolicy -Xmn128M
IntCache: cache: 1, tcache: 1, allocated: 12, tallocated: 94
Launched Version: 1.8
LWJGL: 2.9.1
OpenGL: Intel(R) G45/G43 Express Chipset GL version 2.1.0 - Build 8.15.10.2202, Intel
GL Caps: Using GL 1.3 multitexturing.
Using GL 1.3 texture combiners.
Using framebuffer objects because EXT_framebuffer_object is supported.
Shaders are available because OpenGL 2.1 is supported.
VBOs are available because OpenGL 1.5 is supported.

Using VBOs: Yes
Is Modded: Probably not. Jar signature remains and client brand is untouched.
Type: Client (map_client.txt)
Resource Packs: []
Current Language: English (US)
Profiler Position: N/A (disabled)

This is still occuring for me in 1.8.1. Unless of course I am having a new issue, in which case I would like my ticket reopened. I attached the bug report like you wanted, Kumasasa. Please determine which ticket it falls under.

Paul Smith, in the words of @unknown:

Then finally attach an affected world here

Yes, @unknown, no one except you is having this issue, but according to your crash report, your computer is below the minimum requirements for rurnning Minecraft...

It is subtle, but everyone is having this issue, whether they see it or not. I have seen it in every Minecraft YouTube video made after 1.8. Every single YouTuber has it. Even horse riding has it. Mobs that cannot fly, compared to 1.7.10, move almost half the speed they did before when jumping or being knocked back. It is most seen with slimes. Compare speeds in 1.7.10 with 1.8 in ANY WORLD, because if you do not test and compare it, you will not see it. Also, how do you attach an affected world? And my computer runs Minecraft just fine.

@unknown: To attach a world, save it as a zip/WinRAR file (in Windows click the Share button at the top, then "Zip") and attach it as you would a screenshot/crash report.

Ok, thank you Sonic. Again, Kumasasa, could you please test this bug? I will post a world, but you must perform a side by side comparison of two worlds, 1.7 and 1.8. Or watch a YouTube video of old and new versions. It is necessary to analyze this issue carefully, everyone playing Minecraft is experiencing this issue as of now, including famous YouTubers.

Please give me an answer Kumasasa. You are denying that this bug still exists only based on the amount of duplicates and reports there have been after the bug was declared fixed. I have seen no change nor chance that this bug has been fixed in any way, and since you are making a blind accusation, we can't be sure. You must test this bug, I am growing angry of this nonsense. I'll say it again, if this bug is proved to be separate from this one, reopen my ticket please.

I have attached a world to this bug report. Hopefully I did this right, it should be at the top of the page.

@unknown: Posting a world wont help, since it wont be able to be reproduced on high end systems anyway.
For example my 4GHz i7 have no problem with that world (and no other world either), and I have no slow mobs anywhere. However that is just because my computer can handle the problems with the code.

To give any useful information you should post information about your system.

That said. The game has increased its processor use in a major way compared to 1.7.10.

You do not understand. Mobs are jumping twice as slow as they used to. No ticks are being affected. I am seeing this in famous YouTuber videos, and all minecraft videos on YouTube, so I know it's a problem. You need to do a side by side comparison of old and current versions. Of course I didn't need to, but for your sake you should do a comparison. By some more testing, squids are unaffected while on land, they appear to be the only mob left. Compare the jumping speed of the squid with the other mobs by knocking them back, the squid is significantly faster than the others.

I will keep urging that this exists, I have found too much evidence already. Many people in Youtube videos think they're system is lagging when they see this.

My laptop is what I would consider a low end laptop gaming wise and has no problems with that world with mobs jumping slower.

Could you post a link to a "famous YouTuber video" that shows the problem?

Semi-known YouTuber who has a beefy computer. Plays pure vanilla Minecraft in this video. Hits many mobs, take note of how slowly they get knocked back:

https://m.youtube.com/watch?v=S0_Grxp3l-U

This is a video he made in version 1.6 or 1.7 Watch up to the 6 minute mark and compare the speeds at which the mobs are knocked back by him. In 1.8, they are slow. In 1.7 and below, they are quick.

https://m.youtube.com/watch?v=3uA-es6xjRI&list=PLqBI8mB1lij8M4i30-t0Zu_2OzDhZbPhK

I would like to say that squids are the only mob unaffected by this bug. Spawn one on land and knock it back. Compare that to any other mob, and you'll see it is twice as slow and much smoother, while the squid is quick and normal speed.

With all this evidence, you should be able to reopen my issue that got marked duplicate of this one. I have presented valid evidence, study it.

Can you please stop spamming. This is intended. Mobs are knocked back slower in 1.8. It has nothing to do with tick lag. If you think you have tick lag use command /debug and check if you get less than 20 ticks per second.

This is very easy to test, even without videos. Just hit any mob back once on either 1.7.10 or 1.8.1-pre4 and compare the two. There is an easily recognizable difference between the speeds the mobs mob up and back down.

It is most certainly not resolved.

Tomaz: it's not intended until Mojang says so.

Thank you Jonathan for confirming. Tomaz, I was not spamming, and never said it was a tick issue. You have confirmed that it is not a tick issue, and we have proved here that it is a bug. Therefore, I would like my ticket I originally made about this bug reopened.

I have put together a video on youtube regarding this bug:
http://youtu.be/Bdfs8a3UfKg

The youtube video describes the bug, compares a slow server to my fast computer and so on..
(Watch in 1080p to see everything good like stars being slow and so on)

Everyone please keep in mind that this bug is currently titled "DoMobSpawning is causing reduced tick speed, causing general tick lag", and not "Mobs are 'jumping slower'".
Mobs jumping slower was a side effect of this bug, but that is not what this bug report is about. This bug report is about the gamerule DoMobSpawning.

As of 1.8-pre4, DoMobSpawning causes no noticeable tick lag and has been resolved.

From what I can tell by doing tests myself, mobs are knocked back slightly slower in 1.8 compared to 1.7. Whether that's intended or not, I don't know. It it also seemingly unrelated to tick lag as it happens even with a full 20.00 tickrate.
MC-69655 should be reopened or a new bug report should be created, either way this "slow mobs" issue is not related to DoMobSpawning.

Jono, thanks for clarifying, but no mod has reopened my issue yet. I hope one does soon, as it is now clear that this is an issue.

Pierre Walden, very good video. I'll comment on it later, but you explain it very well.

Reopened MC-69655

I'm not sure if this would be considered the same bug, but the mobs and minecarts are moving slowly in just certain parts of one of my world (I'm in 1.9.4 right now). For example, in this world:

https://dl.dropboxusercontent.com/u/77400058/Eternal%20Survival%20-%20Copy.zip

The minecart at -77, 62, 143 moves really slowly, along with any mobs that are there (it is not FPS lag; the player moves at a normal speed). However, moving a little away from that area, this is not the case, such as with the minecart at 26, 64, 17.