https://gcc.gnu.org/bugzilla/show_bug.cgi?id=25829
--- Comment #32 from Janne Blomqvist <jb at gcc dot gnu.org> --- Interestingly, Linux 4.14 contains a way to avoid a context switch to a threadpool in case the data is already in the page cache: https://kernelnewbies.org/Linux_4.14#head-8c8861fbded3e87631ab06bcd511f5f0d8bfa220 Might be an interesting optimization sometime in the future..