From: Kurt  Stephens <ks.ruby@...>
Date: 2011-07-20T15:21:51+09:00
Subject: [ruby-core:38245] [Ruby 1.9 - Feature #5033] PATCH: 1.9: gc_mark_children: Avoid gc_mark() tail recursion, use goto again.


Issue #5033 has been updated by Kurt  Stephens.


There is a time improvement for Arrays deeply nested at their tails:

Stock:

+ ./miniruby -e '
x = [ nil ]
10000000.times do | i |
  x[0] = [ i ]
  x = x[0]
end
puts :OK
system "ps -l -p #{$$}"
'
OK
  UID   PID  PPID        F CPU PRI NI       SZ    RSS WCHAN     S     ADDR TTY           TIME CMD
  501 96240 84698     4006   0  31  0  2447588   3096 -      S+    fda67e0 ttys009    0:02.28 ./miniruby -e ^Jx = [

real	0m2.293s
user	0m2.275s
sys	0m0.013s


+ git checkout trunk-gc-mark-optimization
Switched to branch 'trunk-gc-mark-optimization'

+ ./miniruby -e '
x = [ nil ]
10000000.times do | i |
  x[0] = [ i ]
  x = x[0]
end
puts :OK
system "ps -l -p #{$$}"
'
OK
  UID   PID  PPID        F CPU PRI NI       SZ    RSS WCHAN     S     ADDR TTY           TIME CMD
  501 20407 84698     4006   0  31  0  2456804   3096 -      S+    fda67e0 ttys009    0:02.08 ./miniruby -e ^Jx = [

real	0m2.096s
user	0m2.074s
sys	0m0.014s


----------------------------------------
Feature #5033: PATCH: 1.9: gc_mark_children: Avoid gc_mark() tail recursion, use goto again.
http://redmine.ruby-lang.org/issues/5033

Author: Kurt  Stephens
Status: Assigned
Priority: Normal
Assignee: Narihiro Nakamura
Category: core
Target version: 1.9.x


Minor GC improvement.

Avoid recurring into gc_mark() when "goto again;" is sufficient.

-- KAS



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