YJIT: Count the number of failed instructions

doc/yjit/yjit.md

@@ -216,7 +216,7 @@ irb(main):001:0> RubyVM::YJIT.runtime_stats
 {:inline_code_size=>340745,
  :outlined_code_size=>297664,
  :all_stats=>true,
- :exec_instruction=>1547816,
+ :yjit_insns_count=>1547816,
  :send_callsite_not_simple=>7267,
  :send_kw_splat=>7,
  :send_ivar_set_method=>72,
@@ -225,8 +225,7 @@ irb(main):001:0> RubyVM::YJIT.runtime_stats
 
 Some of the counters include:
 
-:exec_instruction - how many Ruby bytecode instructions have been executed
-:yjit_insns_count - how many Ruby bytecode instruction have been executed in compiled code
+:yjit_insns_count - how many Ruby bytecode instructions start execution in compiled code
 :binding_allocations - number of bindings allocated
 :binding_set - number of variables set via a binding
 :code_gc_count - number of garbage collections of compiled code since process start

yjit.rb

@@ -158,11 +158,11 @@ def self.runtime_stats(context: false)
     return stats unless Primitive.rb_yjit_stats_enabled_p
 
     side_exits = total_exit_count(stats)
-    total_exits = side_exits + stats[:leave_interp_return]
+    total_exits = side_exits + stats[:failed_insns_count] + stats[:leave_interp_return]
 
     # Number of instructions that finish executing in YJIT.
     # See :count-placement: about the subtraction.
-    retired_in_yjit = stats[:exec_instruction] - side_exits
+    retired_in_yjit = stats[:yjit_insns_count] - stats[:failed_insns_count] - side_exits
 
     # Average length of instruction sequences executed by YJIT
     avg_len_in_yjit = total_exits > 0 ? retired_in_yjit.to_f / total_exits : 0
@@ -322,7 +322,8 @@ def _print_stats(out: $stderr) # :nodoc:
       if stats.key?(:vm_insns_count)
         out.puts "vm_insns_count:        " + format_number(13, stats[:vm_insns_count])
       end
-      out.puts "yjit_insns_count:      " + format_number(13, stats[:exec_instruction])
+      out.puts "yjit_insns_count:      " + format_number(13, stats[:yjit_insns_count])
+      out.puts "failed_insns_count:    " + format_number(13, stats[:failed_insns_count])
       if stats.key?(:ratio_in_yjit)
         out.puts "ratio_in_yjit:         " + ("%12.1f" % stats[:ratio_in_yjit]) + "%"
       end

yjit/src/codegen.rs

@@ -847,14 +847,14 @@ pub fn gen_single_block(
             verify_ctx(&jit, &asm.ctx);
         }
 
+        // :count-placement:
+        // Count bytecode instructions that start execution in generated code.
+        // Note that the increment happens even when the output takes side exit.
+        gen_counter_incr(&mut asm, Counter::yjit_insns_count);
+
         // Lookup the codegen function for this instruction
         let mut status = None;
         if let Some(gen_fn) = get_gen_fn(VALUE(opcode)) {
-            // :count-placement:
-            // Count bytecode instructions that execute in generated code.
-            // Note that the increment happens even when the output takes side exit.
-            gen_counter_incr(&mut asm, Counter::exec_instruction);
-
             // Add a comment for the name of the YARV instruction
             asm.comment(&format!("Insn: {:04} {} (stack_size: {})", insn_idx, insn_name(opcode), asm.ctx.get_stack_size()));
 
@@ -871,6 +871,9 @@ pub fn gen_single_block(
         // If we can't compile this instruction
         // exit to the interpreter and stop compiling
         if status == None {
+            // Count bytecode instructions that cannot be compiled.
+            gen_counter_incr(&mut asm, Counter::failed_insns_count);
+
             if get_option!(dump_insns) {
                 println!("can't compile {}", insn_name(opcode));
             }

yjit/src/stats.rs

@@ -202,8 +202,6 @@ pub(crate) use ptr_to_counter;
 
 // Declare all the counters we track
 make_counters! {
-    exec_instruction,
-
     send_keywords,
     send_klass_megamorphic,
     send_kw_splat,
@@ -369,6 +367,8 @@ make_counters! {
     binding_set,
 
     vm_insns_count,
+    yjit_insns_count,
+    failed_insns_count,
     compiled_iseq_entry,
     compiled_iseq_count,
     compiled_blockid_count,