#33865: Optimize django.core.handlers.wsgi.LimitedStream
-------------------------------------+-------------------------------------
Reporter: Nick Pope | Owner: Nick Pope
Type: | Status: closed
Cleanup/optimization |
Component: HTTP handling | Version: dev
Severity: Normal | Resolution: fixed
Keywords: wsgi, | Triage Stage: Ready for
limitedstream, performance | checkin
Has patch: 1 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
Changes (by Mariusz Felisiak <felisiak.mariusz@…>):
* status: assigned => closed
* resolution: => fixed
Comment:
In [changeset:"b47f2f5b907732d80b164f1f361ae39da94a3fa6" b47f2f5]:
{{{
#!CommitTicketReference repository=""
revision="b47f2f5b907732d80b164f1f361ae39da94a3fa6"
Fixed #33865 -- Optimized LimitedStream wrapper.
The current implementation of LimitedStream is slow because .read()
performs an extra copy into a buffer and .readline() performs two
extra copies. The stream being wrapped is already typically a BytesIO
object so this is unnecessary.
This implementation has largely been untouched for 12 years and,
inspired by a simpler implementation in werkzeug, it was possible to
achieve the following performance improvement:
LimitedStream.read() (single line):
Mean +- std dev: [bench_limitedstream-main] 286 ns +- 6 ns
-> [bench_limitedstream-patch] 227 ns +- 6 ns: 1.26x faster
LimitedStream.readline() (single line):
Mean +- std dev: [bench_limitedstream-main] 507 ns +- 11 ns
-> [bench_limitedstream-patch] 232 ns +- 8 ns: 2.18x faster
LimitedStream.read(8192) (single line):
Mean +- std dev: [bench_limitedstream-main] 360 ns +- 8 ns
-> [bench_limitedstream-patch] 297 ns +- 6 ns: 1.21x faster
LimitedStream.readline(8192) (single line):
Mean +- std dev: [bench_limitedstream-main] 602 ns +- 10 ns
-> [bench_limitedstream-patch] 305 ns +- 10 ns: 1.98x faster
LimitedStream.read() (multiple lines):
Mean +- std dev: [bench_limitedstream-main] 290 ns +- 5 ns
-> [bench_limitedstream-patch] 236 ns +- 6 ns: 1.23x faster
LimitedStream.readline() (multiple lines):
Mean +- std dev: [bench_limitedstream-main] 517 ns +- 19 ns
-> [bench_limitedstream-patch] 239 ns +- 7 ns: 2.16x faster
LimitedStream.read(8192) (multiple lines):
Mean +- std dev: [bench_limitedstream-main] 363 ns +- 8 ns
-> [bench_limitedstream-patch] 311 ns +- 11 ns: 1.17x faster
LimitedStream.readline(8192) (multiple lines):
Mean +- std dev: [bench_limitedstream-main] 601 ns +- 12 ns
-> [bench_limitedstream-patch] 308 ns +- 7 ns: 1.95x faster
Geometric mean: 1.59x faster
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/33865#comment:14>
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