Ruby » Ruby master

thread.c: micro-optimize thread create/join

• thread.c (struct join_arg): restructure and make smaller
  (thread_join_sleep): avoid timeofday() call if forever
  (thread_join): pass join_arg.delay directly
  (rb_thread_inspect_msg): remove, inline into rb_thread_inspect
  (rb_thread_inspect): reduce branching and string creation
• thread_pthread.c (native_set_thread_name): create string directly
  to avoid reparsing. [Misc #10723]

This reduces time in benchmark/bm_vm_thread_create_join.rb by
a few percent.

Minor improvements only:

target 0: 2.1.5 (ruby 2.1.5p273 (2014-11-13 revision 48405) [x86_64-linux])
target 1: trunk (ruby 2.3.0dev (2015-01-16 trunk 49282) [x86_64-linux])
target 2: built (ruby 2.3.0dev (2015-01-16 trunk 49282) [x86_64-linux])

benchmark results:
minimum results in each 3 measurements.
Execution time (sec)
name 2.1.5 trunk built
vm_thread_create_join 1.049 1.242 1.138

Speedup ratio: compare with the result of `2.1.5' (greater is better)
name trunk built
vm_thread_create_join 0.845 0.923

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@49430 b2dd03c8-39d4-4d8f-98ff-823fe69b080e