4 ms·

That is a fun exercise, but I imagine the time to evaluate the conditional expression is a tiny fraction, just a percent or less, than the time it takes to make

That is a fun exercise, but I imagine the time to evaluate the conditional expression is a tiny fraction, just a percent or less, than the time it takes to make the file system calls.

CerryuDu 10mo ago
... not to mention the time it takes to load directory entries and inodes when the cache is cold.
nasretdinov 10mo ago
For many cases you don't even need to make stat() call to determine whether or not the file is a directory (d_type specifically can tell it: https://man7.org/linux/man-pages/man3/readdir.3.html https://man7.org/linux/man-pages/man3/readdir.3.html). That's what allows find(1) to be so quick
- loeg 10mo ago
  You could imagine determining from the parsed expression whether or not stat'ing was required. NFS has readdirplus, but I don't think it ever made its way into Linux/POSIX. (Some filesystems could efficiently return dirents + stat information.)
  - nasretdinov 10mo ago
    > readdirplus Well, it definitely does _something_, because on NFS the subsequent stat() calls after reading the directory names do indeed complete instantly :), at least in my testing.
    - loeg 10mo ago
      I mean, readdirplus as a local filesystem API. Ultimately unix programs are just invoking getdents() (or equivalent) + stat() (or statx, whatever). Linux nfsclient probably caches the result of readdirplus for subsequent stat.