How Fast Is Your OS?

Even after more than twenty years working within and around operating systems I do not have a good answer for these kind of questions. Probably because it is really hard to judge the overall performance of a complex system.

Instead, it is much easier to point to various bottlenecks any complex system will have. These are cases the original architects have overlooked, thought as unimportant or things that just did not scale well with time.

One of my favorite bottlenecks is that listing directories is surprisingly slow on contemporary systems. On my Linux laptop, for instance, it takes more than a minute to list a million directories. This does not feel interactive anymore.

time find /mnt | wc -l
1052689

real	1m29.049s
user	0m1.599s
sys	  0m14.361s