ZJIT: Implement side exit stats (#14357)

1 files changed, 32 insertions, 13 deletions

diff --git a/zjit.rb b/zjit.rb
index b20c110046..cf0896e107 100644
--- a/zjit.rb
+++ b/zjit.rb
@@ -29,9 +29,9 @@ class << RubyVM::ZJIT
     stats = Primitive.rb_zjit_stats(key)
     return stats if stats.nil? || !key.nil?
 
-    if stats.key?(:vm_insns_count) && stats.key?(:zjit_insns_count)
-      stats[:total_insns_count] = stats[:vm_insns_count] + stats[:zjit_insns_count]
-      stats[:ratio_in_zjit] = 100.0 * stats[:zjit_insns_count] / stats[:total_insns_count]
+    if stats.key?(:vm_insn_count) && stats.key?(:zjit_insn_count)
+      stats[:total_insn_count] = stats[:vm_insn_count] + stats[:zjit_insn_count]
+      stats[:ratio_in_zjit] = 100.0 * stats[:zjit_insn_count] / stats[:total_insn_count]
     end
 
     stats
@@ -52,11 +52,13 @@ class << RubyVM::ZJIT
       :gc_time_ns,
       :invalidation_time_ns,
 
-      :total_insns_count,
-      :vm_insns_count,
-      :zjit_insns_count,
+      :side_exit_count,
+      :total_insn_count,
+      :vm_insn_count,
+      :zjit_insn_count,
       :ratio_in_zjit,
     ], buf:, stats:)
+    print_counters_with_prefix(prefix: 'exit_', prompt: 'side exit reasons', buf:, stats:, limit: 20)
 
     buf
   end
@@ -70,9 +72,9 @@ class << RubyVM::ZJIT
   private
 
   def print_counters(keys, buf:, stats:)
-    left_pad = keys.map(&:size).max + 1
+    left_pad = keys.map { |key| key.to_s.sub(/_time_ns\z/, '_time').size }.max + 1
     keys.each do |key|
-      # Some stats like vm_insns_count and ratio_in_zjit are not supported on the release build
+      # Some stats like vm_insn_count and ratio_in_zjit are not supported on the release build
       next unless stats.key?(key)
       value = stats[key]
 
@@ -90,11 +92,28 @@ class << RubyVM::ZJIT
     end
   end
 
-  def print_counters_with_prefix(buf:, stats:, prefix:, prompt:)
-    keys = stats.keys.select { |key| key.start_with?(prefix) && stats[key] > 0 }
-    unless keys.empty?
-      buf << "#{prompt}:\n"
-      print_counters(keys, buf:, stats:)
+  def print_counters_with_prefix(buf:, stats:, prefix:, prompt:, limit: nil)
+    counters = stats.select { |key, value| key.start_with?(prefix) && value > 0 }
+    return if stats.empty?
+
+    counters.transform_keys! { |key| key.to_s.delete_prefix!(prefix) }
+    left_pad = counters.keys.map(&:size).max
+    right_pad = counters.values.map { |value| number_with_delimiter(value).size }.max
+    total = counters.values.sum
+    count = counters.size
+
+    counters = counters.to_a
+    counters.sort_by! { |_, value| -value }
+    counters = counters.first(limit) if limit
+
+    buf << "Top-#{counters.size} " if limit
+    buf << "#{prompt}"
+    buf << " (%.1f%% of all #{count})" % (100.0 * counters.map(&:last).sum / total) if limit
+    buf << ":\n"
+    counters.each do |key, value|
+      padded_key = key.rjust(left_pad, ' ')
+      padded_value = number_with_delimiter(value).rjust(right_pad, ' ')
+      buf << "  #{padded_key}: #{padded_value} (%4.1f%%)\n" % (100.0 * value / total)
     end
   end