Use string evaluation for method instrumentation

This is faster than using define_method since we don't have to keep
block bindings around.

2 files changed, 11 insertions, 9 deletions

diff --git a/lib/gitlab/metrics/instrumentation.rb b/lib/gitlab/metrics/instrumentation.rb
index 1c2f84fb09a..982e35adfc9 100644
--- a/lib/gitlab/metrics/instrumentation.rb
+++ b/lib/gitlab/metrics/instrumentation.rb
@@ -31,16 +31,18 @@ module Gitlab
         alias_name = "_original_#{name}"
         target     = type == :instance ? mod : mod.singleton_class
 
-        target.class_eval do
-          alias_method(alias_name, name)
+        target.class_eval <<-EOF, __FILE__, __LINE__ + 1
+          alias_method :#{alias_name}, :#{name}
 
-          define_method(name) do |*args, &block|
-            ActiveSupport::Notifications.
-              instrument("#{type}_method.method_call", module: mod, name: name) do
-                __send__(alias_name, *args, &block)
+          def #{name}(*args, &block)
+            ActiveSupport::Notifications
+              .instrument("#{type}_method.method_call",
+                          module: #{mod.name.inspect},
+                          name: #{name.inspect}) do
+                #{alias_name}(*args, &block)
               end
           end
-        end
+        EOF
       end
     end
   end
diff --git a/lib/gitlab/metrics/subscribers/method_call.rb b/lib/gitlab/metrics/subscribers/method_call.rb
index 1606134b7e5..0094ed0dc6a 100644
--- a/lib/gitlab/metrics/subscribers/method_call.rb
+++ b/lib/gitlab/metrics/subscribers/method_call.rb
@@ -10,7 +10,7 @@ module Gitlab
         def instance_method(event)
           return unless current_transaction
 
-          label = "#{event.payload[:module].name}##{event.payload[:name]}"
+          label = "#{event.payload[:module]}##{event.payload[:name]}"
 
           add_metric(label, event.duration)
         end
@@ -18,7 +18,7 @@ module Gitlab
         def class_method(event)
           return unless current_transaction
 
-          label = "#{event.payload[:module].name}.#{event.payload[:name]}"
+          label = "#{event.payload[:module]}.#{event.payload[:name]}"
 
           add_metric(label, event.duration)
         end