From: normalperson@...
Date: 2014-07-26T07:52:50+00:00
Subject: [ruby-core:64041] [ruby-trunk - Feature #10096] [Open] [PATCH] use khash for fstring and id_str tables

Issue #10096 has been reported by Eric Wong.

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Feature #10096: [PATCH] use khash for fstring and id_str tables
https://bugs.ruby-lang.org/issues/10096

* Author: Eric Wong
* Status: Open
* Priority: Normal
* Assignee: Koichi Sasada
* Category: core
* Target version: current: 2.2.0
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frozen_strings and global_symbols.id_str hashes are two of the bigger
hashes in Ruby.  They are needlessly ordered and incurs malloc overhead
in every st_table_entry.

Use an unordered open-addressing table which incurs no additional malloc
overhead besides the (larger) table itself.

Reduces "ruby -e exit" (w/RubyGems) by ~200K on eglibc malloc on
amd64 Debian stable due to having fewer allocations

global_symbols.str_id is left unchanged (for now) because it is used for
Symbol.all_symbols where ordering is expected

This introduces no user-visible changes or incompatibility
(unless I added a bug :x).

I chose khash because it is flexible and has (IMHO) a good API.
The API should also be familiar to mruby hackers, as mruby uses
a version of khash.

Future changes:

* covert smaller internal hashes where ordering is not exposed to Ruby users
* (hopefully) other hashes (methods/constants/ivars) hashes [Feature #9614]

(Note: tried a few times in lynx with 503 errors, never had this problem before
in lynx, trying clunky browser now)

---Files--------------------------------
khash.patch (35.5 KB)


-- 
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