Motiejus Jakštys Public Record

Side project retrospective


I spent 7 months building a project (hosted here). Goal: make a fastest known user/group NSS database. I succeeded, kinda. Here is an excerpt from a conclusion I wrote this morning:

This is the fastest known NSS passwd/group implementation for *reads*. On a
corpus with 10k users, 10k groups and 500 average members per group, `id`
takes 17 seconds with the glibc default implementation, 10-17 milliseconds
with a pre-cached `nscd`, ~8 milliseconds with `turbonss`.

Guess what? It is fastest, but not by enough (compared to nscd) to matter.

In lines of code:

 Language        Files        Lines         Code     Comments       Blanks
 Markdown            3          522            0          422          100
 Zig                23         5560         4601          242          717
 Total              26         6082         4601          664          817

This enterprise reminds me of a project I did back at Amazon: I set out to write a faster and more memory efficient throttling daemon (an API-compatible CoralThrottle replacement). It took me ~1 month to build something that can be meaningfully compared. Then while comparing the two I discovered that CoralThrottle was not configured correctly on our environment. When I fixed that, my implementation was even slower (to be expected!) than the upstream one.

Story repeats itself.

How was it?

Loads of fun! I learned Zig quite a bit, contributed to the stdlib. I can comfortably say that it is an amazing language for systems programming. The best parts are C interop and comptime.

The initial motivation cooled down after 1-2 months, then I needed discipline to get back to it. After 5 months of work I did not even start writing the system integration part, so for a very long time I had nothing but unit tests to see the progress.

I did not let myself start another project until this is finished. That was my way to keep the “motivation” up. Now, on the morning of Sunday, 2022-08-21, it is finished.

What’s next?

I will weather-proof the furniture in my terrace. :)

On a serious note, I don’t know what I will do with computers “on the side”. Maybe something with maps, finally. You will find it here.