It could be that bukkit is multi threading or load balancing onto two different cores. Minecraft was designed as a single thread game and not intended to run off of multiple cores. Bukkit attempts to multi thread and when threads are running on multiple cores running at variable speeds, this error can occur.
Ya, I'm probably an idiot noob, and an idiot besides, but what I have found, incidental to knowing anything, is that if I have a utility program that suppresses unnecessary programs from opening up in the background, background programs, ad ware, 'My Little Pony Reader', the game doesn't lag.I would really be interested if anyone with more intelligence than I, at least with computers, would try this and get back to every one. It's update this, update that, but you know, they really don't need to 'update' every 15 minutes. My first search indicated that it doesn't matter how many processors you have, but how many threads you can run and memory is usually sufficient. Junk ware that does you know not what crawls out of all the baseboards and throws a party when you're not monitoring.. Never mind. It's just a thought. probably doesn't amount to anything. Also: this same argument that people need huge main frames to run a game program may be relevant, but what I found with running Fallout 3 was totally different. People were being told in very degrading terms that they weren't "big enough", I guess in terms of their computer, but a person can tell when they are being dogged. It was not a problem with peoples computers, but of course if you have a graphics card the size of a 1970's Cadillac you will have to have a processor and motherboard to keep up with it. It was a problem with (a) files(s). If we are all benefiting from some computer excess somewhere, thank god, but this little computer of mine sometimes plays the game very nicely, but when it doesn't I can tell it is from background interference. Sorry if I offended anyone.
Vanilla 1.7.4 on MineOS Turnkey server. Same error here. I get lag too but only running single core 32bit P4 with 4 gigs of ram. It wasn't a rpoblem until the animals in our corrals hit around 1,000 pieces
But have been getting this error since I fired up the server. Let it run for 30days before reboot. Love this Turnkey....
I run a Bukkit server with 60 plugins and recently, it says that in my console and no one can connect. I run my server through MCProHosting and have 2800 MB of RAM. It says this: 14.02 14:49:16 [Server] WARN Can't keep up! Did the system time change, or is the server overloaded? Running 2838ms behind, skipping 56 tick(s)
Just some general information.
Minecraft is done in Java, Java is single threaded, it can only use one core (one thread). You will need a cpu that can do things quicker.
Minecraft does everything in game in 50ms blocks, if it can't complete what it needs to in each 50ms block it will throw up the "can't keep up error" your game will then get lag
I run modded minecraft systems and I find that the limit that my system can handle is around 70 mods and even then I have to tweak some world gen in the mods so that I limit the amount of lag that I receive.
Also lots of automation is normally a bad idea because it won't fit in the 50ms time frame that Minecraft uses and hence you will get even more lag.
Sorry guys I just had to share this information, I am sure you are all aware of this general information.