Number of CPU cores on Jetson Xavier

When I run htop on the machine I only see CPU utilization for 4 cores. Additionally when I run the linux command

cat /proc/cpuinfo | awk '/^processor/{print $3}' | wc -l

, it returns 4 as well. Xavier’s specs state that it has 8 CPU cores.

What can be causing this discrepancy?

There are different modes for different performance/energy configurations.
These are managed by nvpmodel. You can look at current mode with:

sudo nvpmodel -q

and switch to maxn mode enabling all cores with:

sudo nvpmodel -m 0

You may have a look to /etc/nvpmodel.conf for details about default modes.

Here is also a table that lists the different nvpmodel power presets that are included with L4T for Xavier:

https://docs.nvidia.com/jetson/l4t/Tegra%20Linux%20Driver%20Package%20Development%20Guide/power_management_jetson_xavier.html#wwpID0E0ML0HA

Here you can see the different clock frequencies and cores that are active for each particular preset.

You can also tweak and tailor your own presets by editing the /etc/nvpmodel.conf configuration file that HP mentioned.