Feature #16773: Reduce allocations in net/http

• Status: Open
• Assignee: -
• Target version: -

[timcraft (Tim Craft)]

Some minor patches which help to reduce allocations in net/http, which should benefit any programs making heavy use of net/http:

• patch1.diff sets frozen_string_literal to true for some net/http files (I used ''.dup for mutable strings to match existing code)

• patch2.diff uses (frozen) strings instead of regexps for split separator arguments in lib/net/http/header.rb

• patch3.diff eliminates some calls to self[] in lib/net/http/header.rb which eliminates some unnecessary downcasing and string allocations

With these patches applied I get a modest but significant reduction in allocations using a test script which performs 10 HTTP requests representative of the workload for my use case (using net/http inside a web application). Before (recent master):

Total allocated: 3.21 MB (34031 objects)

After (with patches applied):

Total allocated: 2.99 MB (28756 objects)

I have run make test-all TESTS=net/http and all tests still pass.