I have an 8-core Linux laptop that's been working fine, but the last couple days of last week it started to suddenly run slowly. My project build takes about 8 times longer than normal. The fan will blow constantly while it's running slowly. A reboot seems to clear it up for a while. Top doesn't show any processes consuming the CPU, iostat doesn't show any sudden spikes in any of the metrics it shows.
The only major change I made last week was to install VMWare's conversion tool to run my VM under Virtual Box. I occasionally run a Windows guest on the workstation. I've since uninstalled the tool to try to rule that out as a cause. The issue persists.
What kinds of issues could create a problem that's not visible in top or iostat? Are there other tools that would serve me better to diagnose the problem? Is it possible that the VMWare is connected to the issue in some way, or is that just a coincidence?