di

benchmarks/di_instrument.rb

@@ -1,3 +1,30 @@
+=begin
+
+"Instrumentation" part of Dynamic Instrumentation benchmarks.
+
+Typical result:
+
+Comparison:
+  no instrumentation:   589490.0 i/s
+method instrumentation - cleared:   545807.2 i/s - 1.08x  slower
+line instrumentation - cleared:   539686.5 i/s - 1.09x  slower
+no instrumentation - again:   535761.0 i/s - 1.10x  slower
+method instrumentation:   129159.5 i/s - 4.56x  slower
+line instrumentation - targeted:   128848.6 i/s - 4.58x  slower
+line instrumentation:    10771.7 i/s - 54.73x  slower
+
+In theory, after instrumentation is removed, performance should return to
+the baseline. We are currently observing about a 6-10% performance loss.
+Two theories for why this is so:
+1. Some overhead remains in the code - to be investigated.
+2. The benchmarks were run on a laptop, and during the benchmarking
+process the CPU is heating up and it can't turbo to the same speeds at
+the end of the run as it can at the beginning. Meaning the observed 6-10%
+slowdown at the end is an environmental issue and not an implementation
+problem.
+
+=end
+
 # Used to quickly run benchmark under RSpec as part of the usual test suite, to validate it didn't bitrot
 VALIDATE_BENCHMARK_MODE = ENV['VALIDATE_BENCHMARK'] == 'true'
 
@@ -13,6 +40,10 @@ def test_method
       SecureRandom.uuid
     end
 
+    def not_instrumented
+      SecureRandom.uuid
+    end
+
     # This method must have an executable line as its first line,
     # otherwise line instrumentation won't work.
     # The code in this method should be identical to test_method above.
@@ -192,6 +223,20 @@ def run_benchmark
       raise "Line instrumentation was not cleared (#{calls} calls recorded)"
     end
 
+    Benchmark.ips do |x|
+      benchmark_time = VALIDATE_BENCHMARK_MODE ? { time: 0.01, warmup: 0 } : { time: 10, warmup: 2 }
+      x.config(
+        **benchmark_time,
+      )
+
+      x.report('no instrumentation - again') do
+        Target.new.not_instrumented
+      end
+
+      x.save! 'di-instrument-results.json' unless VALIDATE_BENCHMARK_MODE
+      x.compare!
+    end
+
   end
 
 end