YJIT: add stats for ratio of versions per block (#7653)

yjit.rb

@@ -275,7 +275,11 @@ module RubyVM::YJIT
       $stderr.puts "bindings_set:          " + format_number(13, stats[:binding_set])
       $stderr.puts "compilation_failure:   " + format_number(13, compilation_failure) if compilation_failure != 0
       $stderr.puts "compiled_iseq_count:   " + format_number(13, stats[:compiled_iseq_count])
+      $stderr.puts "compiled_blockid_count:" + format_number(13, stats[:compiled_blockid_count])
       $stderr.puts "compiled_block_count:  " + format_number(13, stats[:compiled_block_count])
+      if stats[:compiled_blockid_count] != 0
+        $stderr.puts "versions_per_block:    " + format_number(13, "%4.3f" % (stats[:compiled_block_count].fdiv(stats[:compiled_blockid_count])))
+      end
       $stderr.puts "compiled_branch_count: " + format_number(13, stats[:compiled_branch_count])
       $stderr.puts "block_next_count:      " + format_number(13, stats[:block_next_count])
       $stderr.puts "defer_count:           " + format_number(13, stats[:defer_count])

yjit/src/core.rs

@@ -1416,6 +1416,11 @@ unsafe fn add_block_version(blockref: BlockRef, cb: &CodeBlock) {
 
     let version_list = get_or_create_version_list(block.get_blockid());
 
+    // If this the first block being compiled with this block id
+    if version_list.len() == 0 {
+        incr_counter!(compiled_blockid_count);
+    }
+
     version_list.push(blockref);
     version_list.shrink_to_fit();
 

yjit/src/stats.rs

@@ -316,6 +316,7 @@ make_counters! {
 
     vm_insns_count,
     compiled_iseq_count,
+    compiled_blockid_count,
     compiled_block_count,
     compiled_branch_count,
     compilation_failure,