Having worked in the past with some pathological codebase that made a horribly huge directory of source, I can confirm that this is unrelated to filesystem - ot

Having worked in the past with some pathological codebase that made a horribly huge directory of source, I can confirm that this is unrelated to filesystem - otherwise opening a file would be also slowed down, and I have found exactly the same behaviour by disabling sorting and other output niceties.