Support stats "ratio_in_yjit"

.github/workflows/test-yjit.yaml

@@ -11,10 +11,16 @@ jobs:
           - '3.2'
           - '3.3'
           # ADD NEW RUBIES HERE
-    name: Test (${{ matrix.os }}, ${{ matrix.ruby }})
+        rubyopt:
+          - '--yjit'
+          - '--yjit --yjit-stats=quiet'
+        exclude:
+          - ruby: '3.2'
+            rubyopt: '--yjit --yjit-stats=quiet'
+    name: Test YJIT (${{ matrix.os }}, ${{ matrix.ruby }} ${{ matrix.rubyopt }})
     runs-on: ${{ matrix.os }}
     env:
-      RUBYOPT: "--yjit"
+      RUBYOPT: ${{ matrix.rubyopt }}
       SKIP_SIMPLECOV: 1
       DD_INSTRUMENTATION_TELEMETRY_ENABLED: false
       DD_REMOTE_CONFIGURATION_ENABLED: false

lib/datadog/core/environment/yjit.rb

@@ -52,6 +52,11 @@ def yjit_alloc_size
           ::RubyVM::YJIT.runtime_stats[:yjit_alloc_size]
         end
 
+        # Ratio of YJIT-executed instructions
+        def ratio_in_yjit
+          ::RubyVM::YJIT.runtime_stats[:ratio_in_yjit]
+        end
+
         def available?
           defined?(::RubyVM::YJIT) \
             && ::RubyVM::YJIT.enabled? \

lib/datadog/core/runtime/ext.rb

@@ -31,6 +31,7 @@ module Metrics
           METRIC_YJIT_OBJECT_SHAPE_COUNT = 'runtime.ruby.yjit.object_shape_count'
           METRIC_YJIT_OUTLINED_CODE_SIZE = 'runtime.ruby.yjit.outlined_code_size'
           METRIC_YJIT_YJIT_ALLOC_SIZE = 'runtime.ruby.yjit.yjit_alloc_size'
+          METRIC_YJIT_RATIO_IN_YJIT = 'runtime.ruby.yjit.ratio_in_yjit'
 
           TAG_SERVICE = 'service'
         end

lib/datadog/core/runtime/metrics.rb

@@ -181,6 +181,10 @@ def flush_yjit_stats
                 Core::Runtime::Ext::Metrics::METRIC_YJIT_YJIT_ALLOC_SIZE,
                 Core::Environment::YJIT.yjit_alloc_size
               )
+              gauge_if_not_nil(
+                Core::Runtime::Ext::Metrics::METRIC_YJIT_RATIO_IN_YJIT,
+                Core::Environment::YJIT.ratio_in_yjit
+              )
             end
           end
         end

sig/datadog/core/environment/yjit.rbs

@@ -11,6 +11,7 @@ module Datadog
         def self?.code_region_size: () -> untyped
         def self?.object_shape_count: () -> untyped
         def self?.yjit_alloc_size: () -> untyped
+        def self?.ratio_in_yjit: () -> untyped
 
         def self?.available?: () -> untyped
       end

spec/datadog/core/runtime/metrics_spec.rb

@@ -198,11 +198,9 @@
           skip('Test only runs on Ruby >= 3.2') if RUBY_VERSION < '3.2.'
         end
 
-        context 'with YJIT enabled and RubyVM::YJIT.stats_enabled? false' do
+        context 'with YJIT enabled' do
           before do
-            unless Datadog::Core::Environment::YJIT.available?
-              skip('Test only runs with YJIT enabled and RubyVM::YJIT.stats_enabled? false')
-            end
+            skip('Test only runs with YJIT enabled') unless Datadog::Core::Environment::YJIT.available?
             allow(runtime_metrics).to receive(:gauge)
           end
 
@@ -248,6 +246,24 @@
             end
           end
         end
+
+        context 'with YJIT enabled and RubyVM::YJIT.stats_enabled? true' do
+          before do
+            skip('Test only runs on Ruby >= 3.3') if RUBY_VERSION < '3.3.'
+            unless Datadog::Core::Environment::YJIT.available? && ::RubyVM::YJIT.stats_enabled?
+              skip('Test only runs with YJIT enabled and RubyVM::YJIT.stats_enabled? true')
+            end
+            allow(runtime_metrics).to receive(:gauge)
+          end
+
+          it do
+            flush
+
+            expect(runtime_metrics).to have_received(:gauge)
+              .with(Datadog::Core::Runtime::Ext::Metrics::METRIC_YJIT_RATIO_IN_YJIT, kind_of(Numeric))
+              .once
+          end
+        end
       end
     end