How do you diagnose slow computing time issues on the Pi?
I have Ubuntu 16.04 installed on a Raspberry Pi 3. All Ubuntu package updates are installed, and I've installed the most recent Pi firmware. However, for simply operations, like extracting small tarballs or installing a package, the Pi can take 30 minutes or more. What's really odd is that if I run
htop, it shows no CPU activity and very little memory usage during this time, so I'm at a loss for why the operations are taking so long.
I've read the SD card can be slow, so I measured it's write speed by running:
dd if=/dev/zero of=/tmp/test.img bs=1M count=100
three times, and the MB/sec readings were 50, 11, 23, for an average of 28 MB/sec, which isn't stellar but wouldn't explain a 1 MB tarball taking minutes to extract.
I tried using
raspi-config to overclock the Pi, but it told me that, "This pi cannot be overclocked", so I guess that's not an option.
I have a small stick-on heatsink attached to the Pi's main processor, and I even bought a tiny fan to blow air over it, so I don't think it's overheating.
What are other things I can do to determine why my Pi is behaving so slowly and speed it up?