* How to enable this feature?
* define USE_DEBUG_COUNTER as 1.
* you can disable to output the result with
RUBY_DEBUG_COUNTER_DISABLE environment variable
even if USE_DEBUG_COUNTER == 1.
* How to add new counter?
* add COUNTER(<name>) line on debug_counter.h.
* include "debug_counter.h"
* insert RB_DEBUG_COUNTER_INC(<name>) line on your favorite place.
* counter output example:
[RUBY_DEBUG_COUNTER] mc_inline_hit 999
[RUBY_DEBUG_COUNTER] mc_inline_miss 3
[RUBY_DEBUG_COUNTER] mc_global_hit 23
[RUBY_DEBUG_COUNTER] mc_global_miss 273
[RUBY_DEBUG_COUNTER] mc_global_state_miss 3
[RUBY_DEBUG_COUNTER] mc_class_serial_miss 0
[RUBY_DEBUG_COUNTER] mc_cme_complement 0
[RUBY_DEBUG_COUNTER] mc_cme_complement_hit 0
[RUBY_DEBUG_COUNTER] mc_search_super 1384
[RUBY_DEBUG_COUNTER] ivar_get_hit 0
[RUBY_DEBUG_COUNTER] ivar_get_miss 0
[RUBY_DEBUG_COUNTER] ivar_set_hit 0
[RUBY_DEBUG_COUNTER] ivar_set_miss 0
[RUBY_DEBUG_COUNTER] ivar_get 431
[RUBY_DEBUG_COUNTER] ivar_set 465
* mc_... is related to method caching.
* ivar_... is related to instance variable accesses.
* compare with dtrace/system tap features, there are completely
no performacne penalties when it is disabled.
* This feature is supported only on __GNUC__ compilers.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@57676 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
