fix: emit sample markers; only call start benchmark in first iteration

Author: not-matthias

core/src/codspeed.cpp

@@ -86,9 +86,14 @@ void CodSpeed::start_benchmark(const std::string &name) {
   }
 
   current_benchmark = uri;
+
+  measurement_add_marker(MARKER_TYPE_SAMPLE_START,
+                         measurement_current_timestamp());
 }
 
 void CodSpeed::end_benchmark() {
+  measurement_add_marker(MARKER_TYPE_SAMPLE_END,
+                         measurement_current_timestamp());
   measurement_set_executed_benchmark(current_benchmark);
 
   benchmarked.push_back(current_benchmark);

google_benchmark/src/benchmark.cc

@@ -566,7 +566,7 @@ void RunBenchmarks(const std::vector<BenchmarkInstance>& benchmarks,
 
 #ifdef CODSPEED_WALLTIME
       auto* codspeed = codspeed::CodSpeed::getInstance();
-      if (codspeed != nullptr) {
+      if (codspeed != nullptr && runner.IsFirstRepetition()) {
         codspeed->start_benchmark(runner.GetBenchmarkName());
       }
 #endif

google_benchmark/src/benchmark_runner.h

@@ -60,6 +60,10 @@ class BenchmarkRunner {
     return GetNumRepeats() != num_repetitions_done;
   }
 
+  bool IsFirstRepetition() const {
+    return num_repetitions_done == 0;
+  }
+
   void DoOneRepetition();
 
   RunResults&& GetResults();