First off, I should say the 1.7.10 server rant GREAT on my machine. From the moment I updated to the 1.8 server performance has been TERRIBLE. If I leave the tick watchdog at the default of 60 seconds I can't even reliably run the server with nobody connected. That is, if I start the server and nobody even tries to join the watchdog will kill it a few minutes later.

So, now I'm setting set max-tick-time to -1 and the server runs but it can't keep up with normal gameplay. Blocks reaper after being broken and basic things like opening a door or a gate take minutes.

The console logs show the "Can't keep up!" warnings:

[05:53:02] User Authenticator #1/INFO: UUID of player bmenrigh is fd931d94-ee87-4b2d-b9c6-71ebe050f387
[05:53:03] [Server thread/INFO]: bmenrigh[/24.6.173.186:46162] logged in with entity id 1658 at (-249649.545
29494024, 102.0, 344.93664003493956)
[05:53:03] [Server thread/INFO]: bmenrigh joined the game
[05:55:10] [Server thread/WARN]: bmenrigh moved wrongly!
[05:55:41] [Server thread/WARN]: Can't keep up! Did the system time change, or is the server overloaded? Running 161930ms behind, skipping 3238 tick(s)
[05:55:47] [Server thread/WARN]: Can't keep up! Did the system time change, or is the server overloaded? Running 6331ms behind, skipping 126 tick(s)
[05:56:52] [Server thread/WARN]: Can't keep up! Did the system time change, or is the server overloaded? Running 52925ms behind, skipping 1058 tick(s)
[05:57:05] [Server thread/WARN]: Can't keep up! Did the system time change, or is the server overloaded? Running 13730ms behind, skipping 274 tick(s)
[05:57:17] [Server thread/WARN]: Can't keep up! Did the system time change, or is the server overloaded? Running 8908ms behind, skipping 178 tick(s)
[05:57:52] [Server thread/WARN]: Can't keep up! Did the system time change, or is the server overloaded? Running 22231ms behind, skipping 444 tick(s)

I thought this might be related to the server regenerating ocean to check if it needs to add ocean monuments but there is no ocean near enough for those chunks to get loaded. I also tried flying around the area my player is in to give the server a chance to load and possibly update / convert any old chunks. None of that has had any effect on performance.

I also thought the issue could be related to CPU time spent compressing network data so I've played around with setting the compression threshold from -1 to 255 to 1024 to 4096 to 16384 and none of those values have helped or had any effect on performance.

I'd love to provide more details about where the server is spending all of its time but I think the F3 debug screen is all client-side performance. For what it's worth, the 1.8 client runs great on my machine. FPS is great and the client never lags.

If there is some debugging or tracing mode I can put the server in I'd be happy to do so to gather useful data.