fixup! feat(google_benchmark): only run benchmark once in instrumentation mode

Author: GuillaumeLagrange

google_benchmark/cmake/Codspeed.cmake

@@ -10,28 +10,21 @@ target_compile_definitions(codspeed
 
 # Step 1: Check if CODSPEED_MODE is set via the command line
 
-# CMake cache kind of breaks this mechanism, keeping it for first time
-# defaulting
-if(NOT DEFINED CODSPEED_MODE)
-    # Step 2: Check the environment variable CODSPEED_MODE
-    if(DEFINED $ENV{CODSPEED_RUNNER_MODE})
-        set(CODSPEED_MODE $ENV{CODSPEED_RUNNER_MODE} FORCE)
+if(DEFINED CODSPEED_MODE)
+    # Define a preprocessor macro based on the build mode
+    if(CODSPEED_MODE STREQUAL "instrumentation")
+        target_compile_definitions(
+            codspeed
+            INTERFACE -DCODSPEED_INSTRUMENTATION
+        )
+    elseif(CODSPEED_MODE STREQUAL "walltime")
+        target_compile_definitions(codspeed INTERFACE -DCODSPEED_WALLTIME)
     else()
-        # Step 3: Default to "instrumentation" if no value is provided
-        set(CODSPEED_MODE "instrumentation")
+        message(
+            FATAL_ERROR
+            "Invalid build mode: ${CODSPEED_MODE}. Use 'instrumentation' or 'walltime'."
+        )
     endif()
 endif()
 
-# Define a preprocessor macro based on the build mode
-if(CODSPEED_MODE STREQUAL "instrumentation")
-    target_compile_definitions(codspeed INTERFACE -DCODSPEED_INSTRUMENTATION)
-elseif(CODSPEED_MODE STREQUAL "walltime")
-    target_compile_definitions(codspeed INTERFACE -DCODSPEED_WALLTIME)
-else()
-    message(
-        FATAL_ERROR
-        "Invalid build mode: ${CODSPEED_MODE}. Use 'instrumentation' or 'walltime'."
-    )
-endif()
-
 message(STATUS "Build mode set to: ${CODSPEED_MODE}")

google_benchmark/src/benchmark.cc

@@ -384,9 +384,9 @@ void RunBenchmarks(const std::vector<BenchmarkInstance>& benchmarks,
 
   // Determine the width of the name field using a minimum width of 10.
 #ifdef CODSPEED_INSTRUMENTATION
-  std::cout << "Codspeed mode: instrumentation" << "\n";
+  Err << "Codspeed mode: instrumentation" << "\n";
 #elif defined(CODSPEED_WALLTIME)
-  std::cout << "Codspeed mode walltime" << "\n";
+  Err << "Codspeed mode: walltime" << "\n";
 #endif
 
   bool might_have_aggregates = FLAGS_benchmark_repetitions > 1;

google_benchmark/src/benchmark_api_internal.cc

@@ -98,6 +98,9 @@ State BenchmarkInstance::RunInstrumented(
     ProfilerManager* profiler_manager) const {
   State st(name_.function_name, 1, args_, 0, 1, timer, manager,
            perf_counters_measurement, profiler_manager);
+  // Do one repetition to avoid flakiness due to inconcistencies in CPU cache
+  // from execution order
+  benchmark_.Run(st);
   codspeed->start_benchmark(name().str());
   benchmark_.Run(st);
   codspeed->end_benchmark();

google_benchmark/src/benchmark_runner.cc

@@ -461,20 +461,22 @@ void BenchmarkRunner::RunProfilerManager(IterationCount profile_iterations) {
 }
 
 void BenchmarkRunner::DoOneRepetition() {
-  assert(HasRepeatsRemaining() && "Already done all repetitions?");
-
-  const bool is_the_first_repetition = num_repetitions_done == 0;
-
 #ifdef CODSPEED_INSTRUMENTATION
   std::unique_ptr<internal::ThreadManager> manager;
   manager.reset(new internal::ThreadManager(b.threads()));
   internal::ThreadTimer timer = internal::ThreadTimer::Create();
+  b.Setup();
   State st = b.RunInstrumented(CodSpeed::getInstance(), &timer, manager.get(),
                                nullptr, nullptr);
+  b.Teardown();
 
   return;
 #endif
 
+  assert(HasRepeatsRemaining() && "Already done all repetitions?");
+
+  const bool is_the_first_repetition = num_repetitions_done == 0;
+
   // In case a warmup phase is requested by the benchmark, run it now.
   // After running the warmup phase the BenchmarkRunner should be in a state as
   // this warmup never happened except the fact that warmup_done is set. Every