Annotate benchmarks

Author: byroot

benchmark/parser.rb

@@ -19,15 +19,20 @@ def benchmark_parsing(name, json_output)
   Benchmark.ips do |x|
     x.report("json")      { JSON.parse(json_output) } if RUN[:json]
     x.report("oj")        { Oj.load(json_output) } if RUN[:oj]
-    x.report("oj strict") { Oj.strict_load(json_output) } if RUN[:oj]
     x.report("Oj::Parser") { Oj::Parser.usual.parse(json_output) } if RUN[:oj]
     x.report("rapidjson") { RapidJSON.parse(json_output) } if RUN[:rapidjson]
     x.compare!(order: :baseline)
   end
   puts
 end
 
+# Oj::Parser is very significanly faster (2.70x) on the nested array benchmark
+# thanks to its stack implementation that saves resizing arrays.
 benchmark_parsing "small nested array", JSON.dump([[1,2,3,4,5]]*10)
+
+# Oj::Parser is significanly faster (~1.5x) on the next 4 benchmarks
+# in large part thanks to its string caching.
+# Other than that we're either a bit slower or a bit faster than regular `Oj.load`.
 benchmark_parsing "small hash", JSON.dump({ "username" => "jhawthorn", "id" => 123, "event" => "wrote json serializer" })
 
 benchmark_parsing "test from oj", <<JSON
@@ -36,4 +41,9 @@ def benchmark_parsing(name, json_output)
 
 benchmark_parsing "twitter.json", File.read("#{__dir__}/data/twitter.json")
 benchmark_parsing "citm_catalog.json", File.read("#{__dir__}/data/citm_catalog.json")
-benchmark_parsing "canada.json", File.read("#{__dir__}/data/canada.json")
+
+# rapidjson is 8x faster thanks to it's much more performant float parser.
+# Unfortunately, there isn't a lot of existing fast float parsers in pure C,
+# and including C++ is problematic.
+# Aside from that, we're faster than other alternatives here.
+benchmark_parsing "float parsing", File.read("#{__dir__}/data/canada.json")