22 characters is significantly less useful than 255 characters.
You can still use more than 22 characters; it just switches to the heap.
nothing I am going to store is ever going to require heap allocations
I would put good money that using 256 bytes everywhere is going to be slower overall than just using the heap when you need more than 22 characters. 22 is quite a lot, especially for keys. ThisReallyLongKey is still only 17.
I don’t use 256 bytes everywhere. I use a mix of 64, 128, and 256 byte strings depending on the specific use case.
In a hot path, having the data inline is much more important than saving a few hundred bytes. Cache efficiency plus eliminating heap allocations has huge performance benefits in a game engine that’s running frames as fast as possible.
It’s not as simple as that, depending on the architecture. Typically they would fetch 64-byte cache lines so your 128 bytes aren’t going to be magically more cached than 128 bytes on the heap.
Avoiding allocations may help but also maybe not. This is definitely in “I don’t believe it until I see benchmarks” realm. I would be really really surprised if the allocation cost was remotely bad enough to justify the “sorry your file is too long” errors.
You can still use more than 22 characters; it just switches to the heap.
I would put good money that using 256 bytes everywhere is going to be slower overall than just using the heap when you need more than 22 characters. 22 is quite a lot, especially for keys.
ThisReallyLongKeyis still only 17.I don’t use 256 bytes everywhere. I use a mix of 64, 128, and 256 byte strings depending on the specific use case.
In a hot path, having the data inline is much more important than saving a few hundred bytes. Cache efficiency plus eliminating heap allocations has huge performance benefits in a game engine that’s running frames as fast as possible.
It’s not as simple as that, depending on the architecture. Typically they would fetch 64-byte cache lines so your 128 bytes aren’t going to be magically more cached than 128 bytes on the heap.
Avoiding allocations may help but also maybe not. This is definitely in “I don’t believe it until I see benchmarks” realm. I would be really really surprised if the allocation cost was remotely bad enough to justify the “sorry your file is too long” errors.
Check out the benchmark I edited in to my original post. These are not user-provided strings in my case.