Use bytearray.take_bytes to speed up asyncio.streams

[cmaloney]

Feature or enhancement

Proposal:

Multiple codepaths in asyncio.streams operate on self._buffer (a bytearray) and then "take" (copy and delete bytes from original) when returning or passing them to other functions. That code pattern can be optimized with .take_bytes() added in gh-139871

Pyperformance:

tb_base.json
============

Performance version: 1.13.0
Python version: 3.15.0a2+ (64-bit) revision 227b9d326ec
Report on Linux-6.17.8-arch1-1-x86_64-with-glibc2.42
Number of logical CPUs: 32
Start date: 2025-11-22 16:18:13.127794
End date: 2025-11-22 16:18:41.207577

tb_asyncio.json
===============

Performance version: 1.13.0
Python version: 3.15.0a2+ (64-bit) revision 6982581e422
Report on Linux-6.17.8-arch1-1-x86_64-with-glibc2.42
Number of logical CPUs: 32
Start date: 2025-11-22 16:13:46.913998
End date: 2025-11-22 16:14:14.140152

### asyncio_tcp ###
Mean +- std dev: 169 ms +- 2 ms -> 143 ms +- 6 ms: 1.18x faster
Significant (t=18.89)

### asyncio_tcp_ssl ###
Mean +- std dev: 546 ms +- 8 ms -> 533 ms +- 6 ms: 1.02x faster
Significant (t=6.02)

Has this already been discussed elsewhere?

No response given

Links to previous discussion of this feature:

No response

Linked PRs

• gh-141863: Use bytearray.take_bytes in asyncio.streams #141864