Improve nogc support by jcrist · Pull Request #93 · msgspec/msgspec

jcrist · 2022-03-31T04:30:51Z

Previously GC tracking was disabled for structs with nogc=True, but kept the same GC-enabled memory layout. This PR changes nogc structs to truly be non-GC types. This reduces memory usage per instance by 16 bytes. It also lets dict and tuple instances containing nogc=True structs to also not be tracked instances, further reducing GC load.
Further optimize the allocation code paths for structs. We now no longer needless track structs just to untrack them later, resulting in a micro speedup. We also optimize at import time tp_setattr and tp_free, rather than branching per-call.
Add a benchmark for GC usage comparing structs, structs with nogc=True, classes, and classes with __slots__. This shows a major reduction in GC pause time for applications with a large number of in-memory Struct instances.
Improve documentation for nogc structs.

jcrist added 3 commits March 30, 2022 14:27

WIP - true nogc

405ae93

Add docs, benchmark

8645866

Add tests

91cb28d

jcrist merged commit 7d11c60 into master Mar 31, 2022

jcrist deleted the true-nogc branch March 31, 2022 04:36

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