Day 7: Laboratories
Megathread guidelines
- Keep top level comments as only solutions, if you want to say something other than a solution put it in a new post. (replies to comments can be whatever)
- You can send code in code blocks by using three backticks, the code, and then three backticks or use something such as https://topaz.github.io/paste/ if you prefer sending it through a URL
FAQ
- What is this?: Here is a post with a large amount of details: https://programming.dev/post/6637268
- Where do I participate?: https://adventofcode.com/
- Is there a leaderboard for the community?: We have a programming.dev leaderboard with the info on how to join in this post: https://programming.dev/post/6631465
Surprised you didn’t trigger the OOM killer. Windows?
Naw, linux. I had a Youtube video running in the background that might have made the problem worse. I could switch desktops and move the mouse (albeit with a lot of lag and jitter) but not close the tab or even hard-close the browser.
Running the same code on my macbook triggered the “a script on this page is slowing down firefox, do you want to wait some more or pause and debug it?” prompt.
Either the OOM killer is not properly set up on my desktop, or it was actually a hot CPU loop that caused the lock-up and not memory pressure. Or some sort of hybrid cpu+mem problem? The code was cloning ever-longer arrays in a for-loop, and from my understanding the event loop for a browser page/tab is not only single-threaded but contains both UI events and script execution (unless you explicitly/specifically shell out to a web worker or the like).
Possibly using up swap space first?
This might be the actual culprit; I don’t think I have any swap space allocated (
htopalways displays0/0for it). I have 48 gigs of RAM, and the “out of memory” error I got on a previous day’s problem didn’t provoke a single slowdown, freeze, or program crash…