Decode BIG-IP performance files

Those files are TMM's idea of resource usage. Remember that TMM is a user space microkernel so it has its own scheduler and memory management. So its idea about "free memory" and "cpu use" is different than the linux kernel's. To read what its statistics are, you can use:

tmctl -a -f <tmstat table file>

This solution article has more information about it:

https://my.f5.com/manage/s/article/K91433389

These files are a binary-only format and the column alignments sometimes change by version so make sure to use matching version tmstat table files and tmctl binary.