+void start_logger(const std::string& fname);
+void* std_aligned_alloc(size_t alignment, size_t size);
+void std_aligned_free(void* ptr);
+// memory aligned by page size, min alignment: 4096 bytes
+void* aligned_large_pages_alloc(size_t size);
+// nop if mem == nullptr
+void aligned_large_pages_free(void* mem);
+
+void dbg_hit_on(bool cond, int slot = 0);
+void dbg_mean_of(int64_t value, int slot = 0);
+void dbg_stdev_of(int64_t value, int slot = 0);
+void dbg_correl_of(int64_t value1, int64_t value2, int slot = 0);
+void dbg_print();
+
+using TimePoint = std::chrono::milliseconds::rep; // A value in milliseconds
+static_assert(sizeof(TimePoint) == sizeof(int64_t), "TimePoint should be 64 bits");
+inline TimePoint now() {
+ return std::chrono::duration_cast<std::chrono::milliseconds>(
+ std::chrono::steady_clock::now().time_since_epoch())
+ .count();
+}
+
+
+enum SyncCout {
+ IO_LOCK,
+ IO_UNLOCK
+};
+std::ostream& operator<<(std::ostream&, SyncCout);
+
+#define sync_cout std::cout << IO_LOCK
+#define sync_endl std::endl << IO_UNLOCK
+
+
+// Get the first aligned element of an array.
+// ptr must point to an array of size at least `sizeof(T) * N + alignment` bytes,
+// where N is the number of elements in the array.
+template<uintptr_t Alignment, typename T>
+T* align_ptr_up(T* ptr) {
+ static_assert(alignof(T) < Alignment);
+
+ const uintptr_t ptrint = reinterpret_cast<uintptr_t>(reinterpret_cast<char*>(ptr));
+ return reinterpret_cast<T*>(
+ reinterpret_cast<char*>((ptrint + (Alignment - 1)) / Alignment * Alignment));
+}
+
+
+// True if and only if the binary is compiled on a little-endian machine
+static inline const union {
+ uint32_t i;
+ char c[4];
+} Le = {0x01020304};
+static inline const bool IsLittleEndian = (Le.c[0] == 4);
+
+
+template<typename T, std::size_t MaxSize>
+class ValueList {
+
+ public:
+ std::size_t size() const { return size_; }
+ void push_back(const T& value) { values_[size_++] = value; }
+ const T* begin() const { return values_; }
+ const T* end() const { return values_ + size_; }
+ const T& operator[](int index) const { return values_[index]; }
+
+ private:
+ T values_[MaxSize];
+ std::size_t size_ = 0;