A brain written in Rust would form only tree-like interconnections, not arbitrary graphs, and would quickly be outcompeted by other organisms relying on GC.
This is almost certainly the wrong metaphor, since there aren't really any instances of animals that are always awake, which seems like an obvious competitive advantage.
A better metaphor is probably that the brain is normally run like a heavily overclocked CPU & with insufficient cooling, so it needs to be turned off frequently to cool down.
So "getting rid of the pause" wouldn't result in getting back time but in melting down the chip.
> This is almost certainly the wrong metaphor, since there aren't really any instances of animals that are always awake, which seems like an obvious competitive advantage.
Except that there are. For example dolphins and other sea based mammals who cannot breath underwater. They do so via sleeping half their brain then flipping over and sleeping the other half. This prevents them from drowning.
Going back to the computer analogy, I always thought it sleep more like a disk defrag rather than GC pause. However as other commenters have pointed out, the brain is so different to any computer we've built that any comparison to a computer methodology would quickly fall apart under even the slightest bit of scrutiny.
There are some animals that don't do anything like a human definition of sleep. Some sharks, for example, who have to keep moving all the time.
Probably any computer-based metaphor we come up with for sleep is going to be crap because brains are not similar to computers, and it is unclear how they work. We don't even know exactly why sleep is necessary.
> which seems like an obvious competitive advantage
I wonder if might be sort of the opposite. A lot of animals have natural downtime built into their schedules. Some animals are active only in the day because they need light to do whatever. Other animals are active only at night so they can avoid predators.
Being active all the time is not necessarily better. Idleness may seem like something you want to avoid (if you think in terms of the modern mindset of maximizing productivity), but activity requires energy. Which means it requires food, which is limited.
So you really would only want the amount of activity that actually helps you survive. Anything else should be eliminated because all activity has a cost.
Also, a bit of a tangent: when it comes to movement, rest is important. Endurance comes from the muscles. Muscles store energy inside themselves (in the form of glycogen), and they recharge slowly, on the order of hours. So we are a bit like an electric car that can run for a while but then needs to sit on a charger for a long time. Anyway, the point is that periods of rest help us keep our muscular charge topped up to 100%, and I'd bet there are situations where having your full endurance available is advantageous.
I suppose bodies could be built for faster muscle recharging, but that might make for a body that is more complicated or demands more resources to maintain. I'm not a biologist, but if I understand correctly, muscles draw energy from the bloodstream, and that energy can be supplied by the digestive system or by the liver converting fat. It's unlikely the digestive system could supply lots of energy fast, so you'd need a higher-throughput liver, which seems like a burden. It also might make it tricky to regulate blood sugar with things producing and consuming it at a high rate.
Point is, there might be advantages to a system where energy is staged near the final point of use in the muscles and can't be recharged all that quickly.
Some bird species too (Albatross, Penguins). I sometimes think that meditation could be a state of mind like this: parts of the brain awoke, parts of it asleep. With the caveat that meditation isn't really very restful, but demanding on its own.
