Performance degradation in Python 3.8 compared to the one from docker-library (python3.8:alpine3.12)
Migrating from docker-library the new python3 package bundled in Alpine3.12, an automated performance test shows a clear degradation.
The test consists in serializing complex JSON messages with orjson and sending them over plain TCP.
The receiver side is outside of the container and always the same.
Performance degrades from ~200,000 messages per second with python3.7:alpine3.10 (or python3.8:alpine3.12) to ~180,000 with alpine:3.12 + apk add python3.
Profiling with py-spy all flame charts seem very similar.
The hot spots in the code are:
- ~37% on TCP
socket.sendall()(non-asyncio) => ~38% on the faster version - ~30% on JSON serialization (with orjson) => 32% on the faster version
In both cases I used the same orjson 3.3.1 binary from manylinux wheel, as well as building different versions from scratch with same Rust version and commands.
Since the profile shapes are so similar in both cases, I am wondering if there is a general performance drop in the interpreter itself...