add performance counting mechanism for MRI debug/tuning purpose.

* 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

1 files changed, 67 insertions, 0 deletions

diff --git a/debug_counter.h b/debug_counter.h
new file mode 100644
index 0000000000..e16d5fae4a
--- /dev/null
+++ b/debug_counter.h
@@ -0,0 +1,67 @@
+/**********************************************************************
+
+  debug_counter.h -
+
+  created at: Tue Feb 21 16:51:18 2017
+
+  Copyright (C) 2017 Koichi Sasada
+
+**********************************************************************/
+
+#ifndef RUBY_DEBUG_COUNTER_H
+#define RUBY_DEBUG_COUNTER_H 1
+
+#ifndef USE_DEBUG_COUNTER
+#define USE_DEBUG_COUNTER 0
+#endif
+
+#if !defined(__GNUC__) && USE_DEBUG_COUNTER
+#error "USE_DEBUG_COUNTER is not supported by other than __GNUC__"
+#endif
+
+enum rb_debug_counter_type {
+#define COUNTER(name) RB_DEBUG_COUNTER_##name
+    COUNTER(mc_inline_hit),
+    COUNTER(mc_inline_miss),
+    COUNTER(mc_global_hit),
+    COUNTER(mc_global_miss),
+    COUNTER(mc_global_state_miss),
+    COUNTER(mc_class_serial_miss),
+    COUNTER(mc_cme_complement),
+    COUNTER(mc_cme_complement_hit),
+    COUNTER(mc_search_super),
+    COUNTER(ivar_get_hit),
+    COUNTER(ivar_get_miss),
+    COUNTER(ivar_set_hit),
+    COUNTER(ivar_set_miss),
+    COUNTER(ivar_get),
+    COUNTER(ivar_set),
+    RB_DEBUG_COUNTER_MAX
+#undef COUNTER
+};
+
+#if USE_DEBUG_COUNTER
+#include "ruby/ruby.h"
+
+extern size_t rb_debug_counter[RB_DEBUG_COUNTER_MAX + 1];
+
+inline static int
+rb_debug_counter_add(enum rb_debug_counter_type type, int add, int cond)
+{
+    if (cond) {
+	rb_debug_counter[(int)type] += add;
+    }
+    return cond;
+}
+
+#define RB_DEBUG_COUNTER_INC(type)                rb_debug_counter_add(RB_DEBUG_COUNTER_##type, 1, 1)
+#define RB_DEBUG_COUNTER_INC_UNLESS(type, cond) (!rb_debug_counter_add(RB_DEBUG_COUNTER_##type, 1, !(cond)))
+#define RB_DEBUG_COUNTER_INC_IF(type, cond)       rb_debug_counter_add(RB_DEBUG_COUNTER_##type, 1, (cond))
+
+#else
+#define RB_DEBUG_COUNTER_INC(type)              ((void)0)
+#define RB_DEBUG_COUNTER_INC_UNLESS(type, cond) (cond)
+#define RB_DEBUG_COUNTER_INC_IF(type, cond)     (cond)
+#endif
+
+#endif /* RUBY_DEBUG_COUNTER_H */