fix: use lightweight callgrind toggle for pause/resume timing

measurement_start()/measurement_stop() write markers and manage benchmark
lifecycle — calling them on every pause/resume corrupts the marker structure
and causes "No results found" errors.

Instead, add measurement_pause()/measurement_resume() that only toggle
CALLGRIND_STOP/START_INSTRUMENTATION without touching markers or stats.

Author: not-matthias

core/include/measurement.hpp

@@ -45,6 +45,10 @@ ALWAYS_INLINE void measurement_stop() {
   instrument_hooks_stop_benchmark_inline(g_hooks);
 }
 
+ALWAYS_INLINE void measurement_pause() { CALLGRIND_STOP_INSTRUMENTATION; }
+
+ALWAYS_INLINE void measurement_resume() { CALLGRIND_START_INSTRUMENTATION; }
+
 ALWAYS_INLINE void measurement_set_executed_benchmark(const std::string& name) {
   auto current_pid = getpid();
   instrument_hooks_executed_benchmark(g_hooks, current_pid, name.c_str());

google_benchmark/include/benchmark/benchmark.h

@@ -1074,6 +1074,9 @@ struct State::StateIterator {
     if (BENCHMARK_BUILTIN_EXPECT(cached_ != 0, true)) {
       return true;
     }
+#ifdef CODSPEED_ANALYSIS
+    measurement_stop();
+#endif
     parent_->FinishKeepRunning();
 
 #ifdef CODSPEED_ANALYSIS
@@ -1100,6 +1103,9 @@ inline BENCHMARK_ALWAYS_INLINE State::StateIterator State::end() {
 #endif
 
   StartKeepRunning();
+#ifdef CODSPEED_ANALYSIS
+  measurement_start();
+#endif
   return StateIterator();
 }
 

google_benchmark/src/benchmark.cc

@@ -273,7 +273,7 @@ void State::PauseTiming() {
   uint64_t pause_timestamp = measurement_current_timestamp();
 #endif
 #ifdef CODSPEED_ANALYSIS
-  measurement_stop();
+  measurement_pause();
 #endif
 
   // Add in time accumulated so far
@@ -314,7 +314,7 @@ void State::ResumeTiming() {
   resume_timestamp_ = measurement_current_timestamp();
 #endif
 #ifdef CODSPEED_ANALYSIS
-  measurement_start();
+  measurement_resume();
 #endif
 }