Isdir in Windows 67 times slower than Linux

[nilshg]

Somewhat old comment but potentially still relevant:

Major performance (I/O?) issue in /mnt/* and in ~ (home)

From there:

Linux has a top-level directory entry cache that means that certain queries (most notably stat calls) can be serviced without calling into the file system at all once an item is in the cache. Windows has no such cache, and leaves much more up to the file systems. A Win32 path like C:\dir\file gets translated to an NT path like ??\C:\dir\file, where ??\C: is a symlink in Object Manager to a device object like \Device\HarddiskVolume4. Once such a device object is encountered, the entire remainder of the path is just passed to the file system, which is very different to the centralized path parsing that VFS does in Linux.

Performance impacts in Julia have previously been discussed here:

Package load speed: Windows vs Linux

My general sense is that Windows performance may get less attention than Linux performance. It seems much more likely that I’m the first one to recognize an issue on Windows. This could be merely because many of the developers and users of Julia tend to primarily work on Linux. The exchange that Kristoffer linked above revealed an issue that was affecting Windows users more than Linux users. stat is regularly used when accessing a file since it determines basic information such as does the file…