Merge pull request #4085 from DataDog/ivoanjo/prof-9470-enable-heap-clean-after-gc-default

[PROF-9470] Enable "heap clean after GC" profiler optimization by default

Author: ivoanjo

.gitlab/benchmarks.yml

@@ -104,16 +104,6 @@ only-profiling-heap:
     DD_PROFILING_EXPERIMENTAL_HEAP_ENABLED: "true"
     ADD_TO_GEMFILE: "gem 'datadog', github: 'datadog/dd-trace-rb', ref: '$CI_COMMIT_SHA'"
 
-only-profiling-heap-clean-after-gc:
-  extends: .benchmarks
-  variables:
-    DD_BENCHMARKS_CONFIGURATION: only-profiling
-    DD_PROFILING_ENABLED: "true"
-    DD_PROFILING_ALLOCATION_ENABLED: "true"
-    DD_PROFILING_EXPERIMENTAL_HEAP_ENABLED: "true"
-    DD_PROFILING_HEAP_CLEAN_AFTER_GC_ENABLED: "true"
-    ADD_TO_GEMFILE: "gem 'datadog', github: 'datadog/dd-trace-rb', ref: '$CI_COMMIT_SHA'"
-
 only-profiling-gvl:
   extends: .benchmarks
   variables:

lib/datadog/core/configuration/settings.rb

@@ -518,13 +518,13 @@ def initialize(*_)
             # Controls if the heap profiler should attempt to clean young objects after GC, rather than just at
             # serialization time. This lowers memory usage and high percentile latency.
             #
-            # Only takes effect when used together with `gc_enabled: true` and `experimental_heap_enabled: true`.
+            # Only has effect when used together with `gc_enabled: true` and `experimental_heap_enabled: true`.
             #
-            # @default false
+            # @default true
             option :heap_clean_after_gc_enabled do |o|
               o.type :bool
               o.env 'DD_PROFILING_HEAP_CLEAN_AFTER_GC_ENABLED'
-              o.default false
+              o.default true
             end
           end
 

spec/datadog/core/configuration/settings_spec.rb

@@ -932,7 +932,7 @@
           context 'is not defined' do
             let(:environment) { nil }
 
-            it { is_expected.to be false }
+            it { is_expected.to be true }
           end
 
           [true, false].each do |value|
@@ -947,10 +947,10 @@
 
       describe '#heap_clean_after_gc_enabled=' do
         it 'updates the #heap_clean_after_gc_enabled setting' do
-          expect { settings.profiling.advanced.heap_clean_after_gc_enabled = true }
+          expect { settings.profiling.advanced.heap_clean_after_gc_enabled = false }
             .to change { settings.profiling.advanced.heap_clean_after_gc_enabled }
-            .from(false)
-            .to(true)
+            .from(true)
+            .to(false)
         end
       end