> but the follow-up stat calls to read file attributes (type, permission, attributes, size) are done one file at a time, so there are opportunities for parallel

> but the follow-up stat calls to read file attributes (type, permission, attributes, size) are done one file at a time, so there are opportunities for parallelization. You may expect so but this is usually not the case. Multiple threads submitting stat or other fs ioctl commands to the disk driver are going to be sequenced and may not be threaded. This is definitely how it works on Windows. Linux is better, but a lot of disk IO is behind the times. io_uring only has read/write so far.