typedload VS simdjson-go

Author of typedload here!

FastAPI relies on (not so fast) pydantic, which is one of the slowest libraries in that category.

Don't expect to find such benchmarks on the pydantic documentation itself, but the competing libraries will have them.

[0] https://ltworf.github.io/typedload/

I wrote typedload, which is significantly faster than pydantic. Just uses normal dataclasses/attrs/NamedTuple, has a better API and is pure Python!

I read all the perftests in the repo. I think they nearly all parse a structure that contains a repetition of the same or similar thing a couple hundred thousand times times and the timing function returns the min and max of 5 attempts. I just picked one example for posting.

Not a Python expert, but could the Pydantic tests be possibly not realistic and/or misleading because they are using kwargs in __init__ [1] to parse the object instead of calling the parse_obj class method [2]? According to some PEPs [3], isn't Python creating a new dictionary for that parameter which would be included in the timing? That would be unfortunate if that accounted for the difference.

Something else I think about is if a performance test doesn't produce a side effect that is checked, a smart compiler or runtime could optimize the whole benchmark away. Or too easy for the CPU to do branch prediction, etc. I think I recall that happening to me in Java in the past, but probably not happened here in Python.

[1] https://github.com/ltworf/typedload/blob/37c72837e0a8fd5f350...

[2] https://docs.pydantic.dev/usage/models/#helper-functions

[3] https://peps.python.org/pep-0692/

Speaking of Go, there's a simdjson implementation for golang too:

> Performance wise, simdjson-go runs on average at about 40% to 60% of the speed of simdjson. Compared to Golang's standard package encoding/json, simdjson-go is about 10x faster.

I haven't tried it yet but I don't really need that speed.

https://github.com/minio/simdjson-go

I agree. For performance-sensitive situations, C/C++ or Rust is the only choice. However, many developers choose Go or other languages for engineering efficiency. A typical use case of SIMD in Go is simdjson-go. Besides, there are plenty of bindings and ports of simdjson. "Other languages" developers also need performance improvement from native instructions such as SIMD.

I suggest to use a streaming library to parse your file. Like jstream or simdjson-go

You can also try comparing with https://github.com/minio/simdjson-go. It does use a different API, however, would be good to compare nevertheless.