I’m sure I’m missing context, and presumably there are other benefits, but 5-15% improvement is such a small step to justify rewriting codebases.
I also wonder how much of an improvement you’d get by just asking for a “simple rewrite” in the existing language. I suspect there are often performance improvements to be had with simple changes in the existing language
Far better justification for a rewrite like this is if it eases maintenance, or simplifies building/testing/distribution. Taking an experienced and committed team of C developers with a mature code base, and retraining them to rewrite their project in Rust for its own sake is pretty absurd. But if you have a team that’s more comfortable in Rust, then doing so could make a lot of sense - and, yes, make it easier to ensure the product is secure and memory-safe.
Disagree - a rewrite for “maintainability” is an engineer saying they want to rewrite in their preferred language. I wouldn’t allow someone on my team to rewrite a core dependency for “maintainability”, but I absolutely would if they suggested it would be faster and safer.
I agree that simple rewriting could have given some if not all perf benefits, but can it be the case that rust forces us to structure code in a way that is for some reason more performant in some cases?
5-15% is a big deal for a low-level foundational code, especially if you get it along with some other guarantees, which may be of greater importance.
There are hopefully very few things that can be done to low level building blocks. A 15% improvement is absolutely worth it for a library as widely used as a compression library.
Even 5% on a hot path are quite the big gains, actually.
Furthermore, they said that they did not expect any performance gains. They did the rewrite for other reasons and got the unexpected bonus of extra performance.
