fixup: add busy-wait sleep

Author: not-matthias

examples/google_benchmark_cmake/sleep_bench.hpp

@@ -5,58 +5,65 @@
 #include <chrono>
 #include <thread>
 
+static inline void busy_sleep_for(std::chrono::nanoseconds duration) {
+  auto start = std::chrono::steady_clock::now();
+  while ((std::chrono::steady_clock::now() - start) < duration) {
+    // Busy-wait
+  }
+}
+
 static void BM_sleep_1us(benchmark::State& state) {
   for (auto _ : state) {
-    std::this_thread::sleep_for(std::chrono::microseconds(1));
+    busy_sleep_for(std::chrono::microseconds(1));
   }
 }
 BENCHMARK(BM_sleep_1us);
 
 static void BM_sleep_10us(benchmark::State& state) {
   for (auto _ : state) {
-    std::this_thread::sleep_for(std::chrono::microseconds(10));
+    busy_sleep_for(std::chrono::microseconds(10));
   }
 }
 BENCHMARK(BM_sleep_10us);
 
 static void BM_sleep_50us(benchmark::State& state) {
   for (auto _ : state) {
-    std::this_thread::sleep_for(std::chrono::microseconds(50));
+    busy_sleep_for(std::chrono::microseconds(50));
   }
 }
 BENCHMARK(BM_sleep_50us);
 
 static void BM_sleep_100us(benchmark::State& state) {
   for (auto _ : state) {
-    std::this_thread::sleep_for(std::chrono::microseconds(100));
+    busy_sleep_for(std::chrono::microseconds(100));
   }
 }
 BENCHMARK(BM_sleep_100us);
 
 static void BM_sleep_1ms(benchmark::State& state) {
   for (auto _ : state) {
-    std::this_thread::sleep_for(std::chrono::milliseconds(1));
+    busy_sleep_for(std::chrono::milliseconds(1));
   }
 }
 BENCHMARK(BM_sleep_1ms);
 
 static void BM_sleep_10ms(benchmark::State& state) {
   for (auto _ : state) {
-    std::this_thread::sleep_for(std::chrono::milliseconds(10));
+    busy_sleep_for(std::chrono::milliseconds(10));
   }
 }
 BENCHMARK(BM_sleep_10ms);
 
 static void BM_sleep_50ms(benchmark::State& state) {
   for (auto _ : state) {
-    std::this_thread::sleep_for(std::chrono::milliseconds(50));
+    busy_sleep_for(std::chrono::milliseconds(50));
   }
 }
 BENCHMARK(BM_sleep_50ms);
 
 static void BM_sleep_100ms(benchmark::State& state) {
   for (auto _ : state) {
-    std::this_thread::sleep_for(std::chrono::milliseconds(100));
+    busy_sleep_for(std::chrono::milliseconds(100));
   }
 }
 BENCHMARK(BM_sleep_100ms);