Reduce memory allocations during tag and metric serialization (#294)

* Reduce memory allocations during tag and metric serialization Co-authored-by: Arthur Schreiber <arthurschreiber@github.com> During memory profiling we noticed a high number of allocations originating from the `Tag`- and `StatSerializer`. This change reduces the amount of allocations on the happy path by applying conditions to return early if the tag or metric names don’t include edge case scenarios. Please see the benchmark comparison below to see the effect <details> <summary>Before</summary> ``` rspec spec/statsd/serialization/tag_serializer_spec.rb:219 Run options: include {:locations=>{"./spec/statsd/serialization/tag_serializer_spec.rb"=>[219]}} Datadog::Statsd::Serialization::TagSerializer #format benchmark ruby 3.3.0 (2023-12-25 revision 5124f9ac75) [x86_64-linux] Warming up -------------------------------------- no tags 2.992M i/100ms global tags 2.999M i/100ms tags Array 161.844k i/100ms tags Hash 92.146k i/100ms tags Array + global tags 127.560k i/100ms tags Hash + global tags 94.333k i/100ms Calculating ------------------------------------- no tags 29.033M (± 4.4%) i/s - 146.589M in 5.059500s global tags 28.592M (± 4.0%) i/s - 143.975M in 5.044502s tags Array 1.690M (± 8.4%) i/s - 8.416M in 5.017852s tags Hash 1.083M (± 6.2%) i/s - 5.437M in 5.042581s tags Array + global tags 1.222M (± 8.2%) i/s - 6.123M in 5.044381s tags Hash + global tags 831.802k (±12.1%) i/s - 4.151M in 5.074196s Comparison: no tags: 29033428.5 i/s global tags: 28592301.5 i/s - same-ish: difference falls within error tags Array: 1690469.5 i/s - 17.17x slower tags Array + global tags: 1222161.7 i/s - 23.76x slower tags Hash: 1082883.0 i/s - 26.81x slower tags Hash + global tags: 831802.3 i/s - 34.90x slower measure IPS Calculating ------------------------------------- no tags 0.000 memsize ( 0.000 retained) 0.000 objects ( 0.000 retained) 0.000 strings ( 0.000 retained) global tags 0.000 memsize ( 0.000 retained) 0.000 objects ( 0.000 retained) 0.000 strings ( 0.000 retained) tags Array 240.000 memsize ( 0.000 retained) 5.000 objects ( 0.000 retained) 4.000 strings ( 0.000 retained) tags Hash 400.000 memsize ( 0.000 retained) 8.000 objects ( 0.000 retained) 4.000 strings ( 0.000 retained) tags Array + global tags 392.000 memsize ( 200.000 retained) 6.000 objects ( 5.000 retained) 4.000 strings ( 3.000 retained) tags Hash + global tags 552.000 memsize ( 200.000 retained) 9.000 objects ( 5.000 retained) 4.000 strings ( 3.000 retained) Comparison: no tags: 0 allocated global tags: 0 allocated - same tags Array: 240 allocated - Infx more tags Array + global tags: 392 allocated - Infx more tags Hash: 400 allocated - Infx more tags Hash + global tags: 552 allocated - Infx more measure memory Finished in 42.34 seconds (files took 0.09172 seconds to load) 2 examples, 0 failures ``` </details> <details> <summary>After</summary> ``` rspec spec/statsd/serialization/tag_serializer_spec.rb:219 Run options: include {:locations=>{"./spec/statsd/serialization/tag_serializer_spec.rb"=>[219]}} Datadog::Statsd::Serialization::TagSerializer #format benchmark ruby 3.3.0 (2023-12-25 revision 5124f9ac75) [x86_64-linux] Warming up -------------------------------------- no tags 3.014M i/100ms global tags 2.956M i/100ms tags Array 243.821k i/100ms tags Hash 124.236k i/100ms tags Array + global tags 165.977k i/100ms tags Hash + global tags 97.519k i/100ms Calculating ------------------------------------- no tags 29.620M (± 2.4%) i/s - 150.715M in 5.091350s global tags 29.984M (± 2.1%) i/s - 150.757M in 5.030275s tags Array 2.487M (± 2.1%) i/s - 12.435M in 5.003250s tags Hash 1.330M (± 2.5%) i/s - 6.709M in 5.046724s tags Array + global tags 1.663M (± 3.7%) i/s - 8.465M in 5.097958s tags Hash + global tags 1.050M (± 3.5%) i/s - 5.266M in 5.021279s Comparison: global tags: 29984432.6 i/s no tags: 29620311.3 i/s - same-ish: difference falls within error tags Array: 2486521.6 i/s - 12.06x slower tags Array + global tags: 1662829.5 i/s - 18.03x slower tags Hash: 1330273.7 i/s - 22.54x slower tags Hash + global tags: 1050157.0 i/s - 28.55x slower measure IPS Calculating ------------------------------------- no tags 0.000 memsize ( 0.000 retained) 0.000 objects ( 0.000 retained) 0.000 strings ( 0.000 retained) global tags 0.000 memsize ( 0.000 retained) 0.000 objects ( 0.000 retained) 0.000 strings ( 0.000 retained) tags Array 120.000 memsize ( 0.000 retained) 2.000 objects ( 0.000 retained) 1.000 strings ( 0.000 retained) tags Hash 280.000 memsize ( 0.000 retained) 5.000 objects ( 0.000 retained) 4.000 strings ( 0.000 retained) tags Array + global tags 272.000 memsize ( 80.000 retained) 3.000 objects ( 2.000 retained) 1.000 strings ( 0.000 retained) tags Hash + global tags 432.000 memsize ( 240.000 retained) 6.000 objects ( 5.000 retained) 4.000 strings ( 3.000 retained) Comparison: no tags: 0 allocated global tags: 0 allocated - same tags Array: 120 allocated - Infx more tags Array + global tags: 272 allocated - Infx more tags Hash: 280 allocated - Infx more tags Hash + global tags: 432 allocated - Infx more measure memory Finished in 42.27 seconds (files took 0.09182 seconds to load) 2 examples, 0 failures ``` </details> <details> <summary>Before</summary> ``` rspec spec/statsd/serialization/stat_serializer_spec.rb:97 Run options: include {:locations=>{"./spec/statsd/serialization/stat_serializer_spec.rb"=>[97]}} Datadog::Statsd::Serialization::StatSerializer benchmark ruby 3.3.0 (2023-12-25 revision 5124f9ac75) [x86_64-linux] Warming up -------------------------------------- no tags 241.660k i/100ms no tags + sample rate 134.558k i/100ms with tags 101.980k i/100ms with tags + sample rate 76.582k i/100ms Calculating ------------------------------------- no tags 2.444M (± 1.0%) i/s - 12.325M in 5.043100s no tags + sample rate 1.361M (± 1.5%) i/s - 6.862M in 5.043675s with tags 1.020M (± 0.8%) i/s - 5.099M in 5.001806s with tags + sample rate 763.286k (± 2.3%) i/s - 3.829M in 5.019571s Comparison: no tags: 2444105.8 i/s no tags + sample rate: 1360915.8 i/s - 1.80x slower with tags: 1019507.1 i/s - 2.40x slower with tags + sample rate: 763286.0 i/s - 3.20x slower measure IPS Calculating ------------------------------------- no tags 160.000 memsize ( 0.000 retained) 4.000 objects ( 0.000 retained) 3.000 strings ( 0.000 retained) no tags + sample rate 240.000 memsize ( 0.000 retained) 5.000 objects ( 0.000 retained) 4.000 strings ( 0.000 retained) with tags 480.000 memsize ( 0.000 retained) 8.000 objects ( 0.000 retained) 7.000 strings ( 0.000 retained) with tags + sample rate 520.000 memsize ( 0.000 retained) 9.000 objects ( 0.000 retained) 8.000 strings ( 0.000 retained) Comparison: no tags: 160 allocated no tags + sample rate: 240 allocated - 1.50x more with tags: 480 allocated - 3.00x more with tags + sample rate: 520 allocated - 3.25x more measure memory Finished in 28.13 seconds (files took 0.09106 seconds to load) 2 examples, 0 failure ``` </details> <details> <summary>After</summary> ``` rspec spec/statsd/serialization/stat_serializer_spec.rb:97 Run options: include {:locations=>{"./spec/statsd/serialization/stat_serializer_spec.rb"=>[97]}} Datadog::Statsd::Serialization::StatSerializer benchmark ruby 3.3.0 (2023-12-25 revision 5124f9ac75) [x86_64-linux] Warming up -------------------------------------- no tags 343.036k i/100ms no tags + sample rate 159.735k i/100ms with tags 140.044k i/100ms with tags + sample rate 89.899k i/100ms Calculating ------------------------------------- no tags 3.401M (± 3.8%) i/s - 17.152M in 5.052869s no tags + sample rate 1.596M (± 0.4%) i/s - 7.987M in 5.004351s with tags 1.400M (± 1.6%) i/s - 7.002M in 5.004013s with tags + sample rate 960.181k (± 0.9%) i/s - 4.855M in 5.056339s Comparison: no tags: 3400803.1 i/s no tags + sample rate: 1595983.7 i/s - 2.13x slower with tags: 1399691.8 i/s - 2.43x slower with tags + sample rate: 960181.4 i/s - 3.54x slower measure IPS Calculating ------------------------------------- no tags 120.000 memsize ( 0.000 retained) 3.000 objects ( 0.000 retained) 2.000 strings ( 0.000 retained) no tags + sample rate 200.000 memsize ( 0.000 retained) 4.000 objects ( 0.000 retained) 3.000 strings ( 0.000 retained) with tags 320.000 memsize ( 0.000 retained) 4.000 objects ( 0.000 retained) 3.000 strings ( 0.000 retained) with tags + sample rate 360.000 memsize ( 0.000 retained) 5.000 objects ( 0.000 retained) 4.000 strings ( 0.000 retained) Comparison: no tags: 120 allocated no tags + sample rate: 200 allocated - 1.67x more with tags: 320 allocated - 2.67x more with tags + sample rate: 360 allocated - 3.00x more measure memory Finished in 28.13 seconds (files took 0.08992 seconds to load) 2 examples, 0 failures ``` </details> * always call "#to_s" and fix typo * rename name to metric_name and avoid allocations when converting symbol to string
DataDog · Sep 18, 2024 · a3291f2 · a3291f2
1 parent 517b830
commit a3291f2
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Showing 4 changed files with 42 additions and 16 deletions.
diff --git a/lib/datadog/statsd/serialization/stat_serializer.rb b/lib/datadog/statsd/serialization/stat_serializer.rb
@@ -10,20 +10,20 @@ def initialize(prefix, global_tags: [])
           @tag_serializer = TagSerializer.new(global_tags)
         end
 
-        def format(name, delta, type, tags: [], sample_rate: 1)
-          name = formated_name(name)
+        def format(metric_name, delta, type, tags: [], sample_rate: 1)
+          metric_name = formatted_metric_name(metric_name)
 
           if sample_rate != 1
             if tags_list = tag_serializer.format(tags)
-              "#{@prefix_str}#{name}:#{delta}|#{type}|@#{sample_rate}|##{tags_list}"
+              "#{@prefix_str}#{metric_name}:#{delta}|#{type}|@#{sample_rate}|##{tags_list}"
             else
-              "#{@prefix_str}#{name}:#{delta}|#{type}|@#{sample_rate}"
+              "#{@prefix_str}#{metric_name}:#{delta}|#{type}|@#{sample_rate}"
             end
           else
             if tags_list = tag_serializer.format(tags)
-              "#{@prefix_str}#{name}:#{delta}|#{type}|##{tags_list}"
+              "#{@prefix_str}#{metric_name}:#{delta}|#{type}|##{tags_list}"
             else
-              "#{@prefix_str}#{name}:#{delta}|#{type}"
+              "#{@prefix_str}#{metric_name}:#{delta}|#{type}"
             end
           end
         end
@@ -37,17 +37,18 @@ def global_tags
         attr_reader :prefix
         attr_reader :tag_serializer
 
-        def formated_name(name)
-          if name.is_a?(String)
-            # DEV: gsub is faster than dup.gsub!
-            formated = name.gsub('::', '.')
+        def formatted_metric_name(metric_name)
+          formatted = Symbol === metric_name ? metric_name.name : metric_name.to_s
+
+          if formatted.include?('::')
+            formatted = formatted.gsub('::', '.')
+            formatted.tr!(':|@', '_')
+            formatted
+          elsif formatted.include?(':') || formatted.include?('@') || formatted.include?('|')
+            formatted.tr(':|@', '_')
           else
-            formated = name.to_s
-            formated.gsub!('::', '.')
+            formatted
           end
-
-          formated.tr!(':|@', '_')
-          formated
         end
       end
     end

diff --git a/lib/datadog/statsd/serialization/tag_serializer.rb b/lib/datadog/statsd/serialization/tag_serializer.rb
@@ -73,7 +73,9 @@ def to_tags_list(tags)
         end
 
         def escape_tag_content(tag)
-          tag.to_s.delete('|,')
+          tag = tag.to_s
+          return tag unless tag.include?('|')
+          tag.delete('|,')        
         end
 
         def dd_tags(env = ENV)

diff --git a/spec/statsd/serialization/stat_serializer_spec.rb b/spec/statsd/serialization/stat_serializer_spec.rb
@@ -92,6 +92,22 @@
         expect(subject.format('somecount', 42, 'c', tags: message_tags, sample_rate: 0.5)).to eq 'swag.somecount:42|c|@0.5|#globaltag1:value1,msgtag2:value2'
       end
     end
+
+    context "metric name contains unsupported characters" do
+      it 'does not alter the provided metric name when containing ::' do
+        input = 'somecount::test'
+        output = subject.format(input, 1, 'c')
+        expect(output).to eq 'somecount.test:1|c'
+        expect(input).to eq 'somecount::test'
+      end
+
+      it 'does not alter the provided metric name when containing :|@' do
+        input = 'somecount:|@test'
+        output = subject.format(input, 1, 'c')
+        expect(output).to eq 'somecount___test:1|c'
+        expect(input).to eq 'somecount:|@test'
+      end
+    end
   end
 
   context 'benchmark' do

diff --git a/spec/statsd/serialization/tag_serializer_spec.rb b/spec/statsd/serialization/tag_serializer_spec.rb
@@ -142,6 +142,13 @@
       it 'formats frozen tags correctly' do
         expect(subject.format(['name:foobarfoo'.freeze])).to eq 'name:foobarfoo'
       end
+
+      it 'does not alter the provided tag value when containing unsupported characters' do
+        input = 'name|foobar'
+        output = subject.format([input])
+        expect(output).to eq 'namefoobar'
+        expect(input).to eq 'name|foobar'
+      end
     end
 
     context '[testing management of env vars]' do