As the title suggests, I am having issue with high CPU utilisation using CraftBukkit under FreeBSD 8.1. Information is provided below. Below is the output of "uname -a && java -version": FreeBSD [DOMAIN ADDRESS REMOVED] 8.1-RELEASE FreeBSD 8.1-RELEASE #0: Mon Jul 19 02:36:49 UTC 2010 email@example.com:/usr/obj/usr/src/sys/GENERIC amd64 java version "1.6.0_03-p4" Java(TM) SE Runtime Environment (build 1.6.0_03-p4-root_12_oct_2010_03_13-b00) Java HotSpot(TM) 64-Bit Server VM (build 1.6.0_03-p4-root_12_oct_2010_03_13-b00, mixed mode) 4. Are you running any wrappers? McMyAdmin, mcadmin, Hamachi, etc? No. 5. What build of CraftBukkit are you running? (do NOT say latest. Say the build number.) I am running CraftBukkit build #1337, I will additionally paste the server.log entry for it below: Craftbukkit version git-Bukkit-0.0.0-1131-g86b7fa8-b1337jnks (MC: 1.8.1) 6. What command are you using to run your CraftBukkit server? -Xincgc -Xmx2G -Xss32m -XX:+DisableExplicitGC -jar 7. What plugins are you running? This issue occurs without any plugins installed. 8. What error are you getting (post your server.log file)? I am not receiving any errors. 9. What have you tried already? I have tried the following startup parameters, all to no avail: -Xmx1536M -Xms256M -Xss24m -XX:MaxHeapFreeRatio=90 -XX:+UseParallelGC -XXarallelGCThreads=4 -XX:MaxGCPauseMillis=450 -jar -Xmx1024M -Xms256M -Xss32m -XX:MaxHeapFreeRatio=90 -XX:+UseParallelGC -XXarallelGCThreads=4 -XX:MaxGCPauseMillis=450 -verbose:GC -Xloggc:gc.log -jar -Xmx2048M -Xms256M -Xss32m -XX:+UseConcMarkSweepGC -XX:+UseParNewGC -XXarallelGCThreads=1 -XX:+CMSParallelRemarkEnabled -XX:+DisableExplicitGC -XX:MaxGCPauseMillis=500 -XX:SurvivorRatio=8 -XX:TargetSurvivorRatio=90 -verbose:GC -Xloggc:gc.log -jar" -Xincgc -Xmx2G -Xss32m -XX:+DisableExplicitGC -jar" I have tried the following CraftBukkit Builds: #1185 #1317 #1337 I have tried both with and without plugins, I have the same issue, therefore plugins aren't the issue. I have tried using two blank worlds, and my pre-existing world. 10. Have you tried any of the things below? Run the vanilla Minecraft server (no Craftbukkit) I tried this, the CPU usage is far lower than with craftbukkit running. Two people flying on creative mode on vanilla uses less CPU than one person stood still on craftbukkit. Update your CraftBukkit Build: As stated above, I have tried with three seperate builds of CraftBukkit, included the latest RB. Remove all your plugins and try with just CraftBukkit. Does the error/problem still occur: Yes, I have tested both with and without plugins, and there is no noticable change in CPU usage. Update your plugins: Irrelevant considering the post above. Add in a single plugin: Also Irrelevant considering two posts above. Additional information: The server has the following CPU: Intel(R) Core(TM)2 Quad CPU Q9650 @ 3.00GHz When a single player logs on to the Minecraft server, the cpu usage is around 15-20%, and for every player who joins, an extra 5-10% is added to the CPU load. In constrast, with vanilla minecraft, it idles at around 11% CPU, and each player adds around 2% to the CPU. I will hopefully be able to add more useful figures to this section in the near future.