Building raster overviews with gdal_translate in parallel, in a portion of time taken by gdaladdo
There's a blog post explaining the whole enchilada here: https://blog.viasig.com/2020/03/overviews-gdal-em-modo-turbo/
This script automates creating overviews with 3 parallel gdal_translate commands, instead of using gdaladdo. In limited tests it is 20% faster, and takes 30% less disk space.
Should be simple enough to port to Linux.