Will post cpu profiles tomorrow.
Quick update: No significant difference in running time when I try max_background_compact=20, 10, 1 (default).
And no significant difference between jemalloc and stdmalloc. Note that jemalloc is the default malloc for embedded build. To disable it, you do go build -tags="embed stdmalloc". I run the two different loader binaries (with different file sizes) and see no significant difference in running time.
Note: On my machine running time can fluctuate quite a bit. It varies between 7.5min+ to 8min+ for loading only rdf-films.gz. It is hard to draw any conclusion if the improvement is small. Perhaps, I should run some benchmarks instead.