Bug #5946: Remove too early and unnecessary calls to heaps_increment

• Status: Rejected
• Assignee: authorNari (Narihiro Nakamura)
• Target version: 2.0.0
• ruby -v: ruby 2.0.0dev (2012-01-29 trunk 34394) [i686-linux]

[funny_falcon (Yura Sokolov)]

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

[authorNari (Narihiro Nakamura)]

• Status changed from Open to Rejected

Hi.

I reject it because lazy sweeping would spent much time if heap is full.
https://github.com/funny-falcon/ruby/commit/f07354e714e4ee6e4b1c6805d4dc111cb434f50a#L0R2314

I reject it. Please see r32894.
https://github.com/funny-falcon/ruby/commit/f07354e714e4ee6e4b1c6805d4dc111cb434f50a#L0R2629

Thanks :)

[funny_falcon (Yura Sokolov)]

Could you make a benchmark, please?

My benchmark shows 1% improvement when patch is applied to ruby-trunk and 6% after other patch, which I want to introduce today's evening/tomorow .

[funny_falcon (Yura Sokolov)]

I remade benchmark. It seems that I was wrong.

Excuse me.