From: Yura Sokolov <funny.falcon@...>
Date: 2012-01-30T13:12:21+09:00
Subject: [ruby-core:42258] [ruby-trunk - Bug #5946][Open] Remove too early and unnecessary calls to heaps_increment


Issue #5946 has been reported by Yura Sokolov.

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Bug #5946: Remove too early and unnecessary calls to heaps_increment
https://bugs.ruby-lang.org/issues/5946

Author: Yura Sokolov
Status: Open
Priority: Normal
Assignee: Narihiro Nakamura
Category: core
Target version: 2.0.0
ruby -v: ruby 2.0.0dev (2012-01-29 trunk 34394) [i686-linux]


Too early call in `lazy_sweep` slows down sweep phase, cause while loop breaks on `if (has_free_object) { ... return TRUE;}` .

Heap expand in `gc_clear_mark_on_sweep_slots` unnecessary expands number of heaps, which slows down iterations in `rb_objspace_call_finalizer`, and `gc_marks` (cause we often need to binary search heap for pointer).

Testing suit: https://gist.github.com/1702301

Before:

    $ sh siege.sh
    Transaction rate:	      114.71 trans/sec
    Transaction rate:	      117.84 trans/sec
    Transaction rate:	      121.62 trans/sec
    $ sh siege.sh
    Transaction rate:	      118.72 trans/sec
    Transaction rate:	      120.32 trans/sec
    Transaction rate:	      121.12 trans/sec

After:

    $ sh siege.sh
    Transaction rate:	      121.62 trans/sec
    Transaction rate:	      122.12 trans/sec
    Transaction rate:	      123.12 trans/sec
    $ sh siege.sh
    Transaction rate:	      123.25 trans/sec
    Transaction rate:	      121.94 trans/sec
    Transaction rate:	      123.52 trans/sec

https://github.com/ruby/ruby/pull/89


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