[Fyren]

If a plugin is only running SP code (e.g. a loop is actually taking a long time to run), then it couldn't peg the CPU at 100% without causing the server to at least stutter. The server and SP are mostly just one thread, so SP running something prevent the server from processing game frames or running console commands. Something like that happening would clearly show on a client's netgraph.

It's possible to call something in the server or an extension that could take up all your extra frame time, I guess. It doesn't seem likely.

On the profiler output (while I haven't looked at in a long time, so I might be misremembering how it looks), you'd probably want to look at the average frame time and peak columns. SP-related things will have the .smx filename in the name. Things with peaks over 1 / tickrate are slow enough to be a problem.

If you can start the server with no plugins and it will eventually use 100% CPU, then it's pretty clearly not a plugin's problem, so you should see if that happens.