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Comment by philosopher1234 | Hacker News Reader

What makes it slower?

It’s hard for Go to beat C in a straight benchmark - Go is garbage collected and allocations often have extra overhead due to the memory layout of interfaces.

In addition, a lot of optimizations (like loop unrolling) are left on the table to preserve Go's fast compile times.

Gccgo is the answer here.

Gccgo at its core may be fast but when it comes to how the go frontend interpret it to gcc ir that pales in comparison than just straight up optimizating the Go compiler

There’ll more opportunities for more optimizations since they move to SSA ir since 1.5 and in turn compile time will definitely go down

I was surprised with the announcement that Go's standard compiler had register allocation for function arguments[0] added to it. This seemed like table stakes for a very long time but it really illustrated just how Go's compiler is much, much simpler than most in many areas.

On one hand it makes you wonder how much could be squeezed out of Go and how many basic things they're still leaving out of the compiler. On the other it tells part of the story of why Go compiles fast with the backdrop that despite this lack of work by the compiler people use Go productively all day and deliver services they are happy with from a performance perspective.

[0] - https://go.dev/doc/go1.17#compiler (2021-08)

I wonder if they'll ever switch to a "normal = fast compile, low optimisation; release = slow compile, high optimisation" model like Rust. Although I suppose other languages already have the "high optimisation" parts covered (rust, julia, python+numpy, etc.) which might make it a fool's errand.

It goes to show the impact of optimizing from top-down instead of bottom-up can have. Go was designed with performance in mind ("mechanical sympathy") as opposed to most other GC languages for which performance was an afterthought.

If you get high-level language constructs right, you'll get great performance by default, even with a simple compiler:

- structs instead of objects

- value types

- exposed pointers

- straightforward allocation semantics

Most compilers out there are busy fighting bad language designs. There's only so much a compiler can do when faced with fat objects hidden behind a spider web of pointers. So they have to do these microoptimizations to claw back at least some performance.

It is a matter of skill, Go can do manual memory management and stack allocation just as well.

Also, Go barely optimizes code, that’s how it compiles as fast.

Not only Go compiler is not as good at optimisation as C/C++/Rust/Zig/D compilers, but also Go FFI to C has significant overhead, which means there is often not much point in using low-level Linux APIs for performance advantage. Same problem like with Java. And in a database system you quite likely want a fine degree of control with non-standard stuff.

However, it is absolutely plausible for Go-calling-Go to beat Go-calling-C-via-CGo, since CGo has plenty of overhead.

Other than what the other responders said, since it uses a C to Go compiler, I'd imagine the Go code that's generated isn't as fast as handwritten Go code could be.

C -> GPT -> Go -> Edit -> commit?

-> fail to compile / crash at startup

My guess is that over the years many optimizations have gone into SQLite that would take a lot of effort to catch up to.

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