feat: cache line alignment

milsanore · milsanore · commit 5f97407c796c · 2025-10-24T14:23:02.000+11:00
diff --git a/README.md b/README.md
@@ -151,6 +151,7 @@ NB: this app uses `make` as a recipe book, but it's not essential:
   - FTXUI snapshot testing
 - performance
   - ✅ store prices and sizes as integrals (ticks as `uint64_t`) for performance
+  - ✅ cache line alignment
   - release compile flags
   - profiling (valgrind/cachegrind)
   - profile-guided optimization (pgo)
diff --git a/src/binance/auth.h b/src/binance/auth.h
@@ -1,9 +1,11 @@
 #pragma once
 
 #include <mutex>
+#include <new>
 #include <string>
 #include <vector>
 
+#include "../utils/env.h"
 #include "iauth.h"
 
 namespace binance {
@@ -41,7 +43,7 @@ class Auth final : public IAuth {
  private:
   // when authenticating with Binance, each session authenticates independently,
   // and in parallel. requires synchronisation because of file access.
-  mutable std::mutex mutex_;
+  alignas(utils::Env::CACHE_LINE_SIZE) mutable std::mutex mutex_;
 
   std::string& api_key_;
   std::string& private_pem_path_;
diff --git a/src/binance/fix_app.h b/src/binance/fix_app.h
@@ -42,10 +42,10 @@ class FixApp final : public FIX::Application, public FIX44::MessageCracker {
   // TODO: we will have one of these per instrument
 
  private:
-  static constexpr std::string THREAD_NAME_ = "tradercppFIX2";
-  static constexpr std::string PRICE_SESSION_QUALIFIER_ = "PX";
-  static constexpr std::string TRADE_SESSION_QUALIFIER_ = "TX";
-  static constexpr std::string ORDER_SESSION_QUALIFIER_ = "OX";
+  static inline constexpr std::string THREAD_NAME_ = "tradercppFIX2";
+  static inline constexpr std::string PRICE_SESSION_QUALIFIER_ = "PX";
+  static inline constexpr std::string TRADE_SESSION_QUALIFIER_ = "TX";
+  static inline constexpr std::string ORDER_SESSION_QUALIFIER_ = "OX";
   const std::vector<std::string>& symbols_;
   const std::unique_ptr<IAuth> auth_;
   const uint16_t MAX_DEPTH_;
diff --git a/src/binance/message_handling_mode.h b/src/binance/message_handling_mode.h
@@ -19,7 +19,7 @@ struct MessageHandlingMode {
     SEQUENTIAL = 2,
   };
 
-  static constexpr uint16_t FIELD_ID = 25'035;
+  static inline constexpr uint16_t FIELD_ID = 25'035;
 
   static constexpr uint16_t to_int(Mode m) noexcept { return static_cast<uint16_t>(m); }
 
diff --git a/src/binance/worker.h b/src/binance/worker.h
@@ -18,7 +18,7 @@ namespace binance {
 /// @brief Binance DI container
 class Worker final {
  public:
-  static constexpr std::string THREAD_NAME_ = "tradercppFIX1";
+  static inline constexpr std::string THREAD_NAME_ = "tradercppFIX1";
   Worker(std::unique_ptr<FixApp> app,
          std::unique_ptr<FIX::FileStoreFactory> store,
          FIX::SessionSettings settings,
diff --git a/src/core/bid_ask.h b/src/core/bid_ask.h
@@ -2,10 +2,12 @@
 
 #include <cmath>
 
+#include "../utils/env.h"
+
 namespace core {
 
 /// @brief basic bid/ask level
-struct BidAsk {
+struct alignas(utils::Env::CACHE_LINE_SIZE) BidAsk {
  public:
   BidAsk() = default;
   explicit BidAsk(u_int64_t bidsz, u_int64_t bidpx, u_int64_t askpx, u_int64_t asksz)
@@ -14,7 +16,7 @@ struct BidAsk {
   // NB: using UINT64_MAX as a sentinel value.
   // maybe it's smarter to use UINT64_MAX-1 as a sentinel,
   // in order to catch overflow prices in the market?
-  static constexpr u_int64_t SENTINEL_ = UINT64_MAX;
+  static inline constexpr u_int64_t SENTINEL_ = UINT64_MAX;
 
   u_int64_t bid_sz = SENTINEL_;
   u_int64_t bid_px = SENTINEL_;
diff --git a/src/core/order_book.h b/src/core/order_book.h
@@ -8,6 +8,7 @@
 #include <mutex>
 
 #include "../binance/symbol.h"
+#include "../utils/env.h"
 #include "absl/container/btree_map.h"
 #include "bid_ask.h"
 
@@ -37,7 +38,7 @@ class OrderBook {
  private:
   // mutex for reading/writing to bid/ask maps
   // NB: UI-bound, so performance is acceptable
-  mutable std::mutex mutex_;
+  alignas(utils::Env::CACHE_LINE_SIZE) mutable std::mutex mutex_;
   /// @brief sorted list of bids (descending), key=price, value=size
   absl::btree_map<uint64_t, uint64_t, std::greater<>> bid_map_;
   /// @brief sorted list of offers (ascending), key=price, value=size
diff --git a/src/core/trade.h b/src/core/trade.h
@@ -3,27 +3,29 @@
 #include <cmath>
 
 #include "../binance/side.h"
+#include "../utils/env.h"
 
 using binance::Side;
 using binance::SideEnum;
 
 namespace core {
 
 /// @brief Binance trade object
-struct Trade {
+struct alignas(utils::Env::CACHE_LINE_SIZE) Trade {
  public:
-  Trade(std::string time,
-        const SideEnum side,
+  Trade(const SideEnum side,
         const uint64_t px,
         const uint64_t sz,
-        const uint64_t id)
-      : time(std::move(time)), side(side), px(px), sz(sz), id(id) {}
+        const uint64_t id,
+        std::array<char, 16> time)
+      : side(side), px(px), sz(sz), id(id), time(time) {}
 
-  std::string time;
-  SideEnum side;
   uint64_t px;
   uint64_t sz;
   uint64_t id;
+  SideEnum side;
+  // 15 characters + newline, e.g. "07:17:50.031794"
+  std::array<char, 16> time;
 };
 
 }  // namespace core
diff --git a/src/main.cpp b/src/main.cpp
@@ -6,6 +6,7 @@
 #include "spdlog/sinks/basic_file_sink.h"
 #include "spdlog/spdlog.h"
 #include "ui/app/ui_app.h"
+#include "utils/env.h"
 #include "utils/threading.h"
 
 int main() {
@@ -19,8 +20,8 @@ int main() {
   // Set a global pattern without the logger name
   spdlog::set_pattern("[%Y-%m-%d %H:%M:%S.%e] [%^%l%$] [%t] %v");
   spdlog::flush_every(std::chrono::microseconds(100));
-
   spdlog::info("hello");
+  utils::Env::log_arch();
 
   // Binance market data connectivity
   auto b_conf = binance::Config::from_env();
diff --git a/src/ui/app/ui_app.cpp b/src/ui/app/ui_app.cpp
@@ -77,7 +77,7 @@ void App::start() {
   const ftxui::Component row2 =
       Horizontal({Vertical({wallet_box_.get_component() | flex}) | flex,
                   Vertical({log_box_->get_component() | flex}) | flex});
-  const ftxui::Component root = Vertical({row1 | size(HEIGHT, EQUAL, 20), row2 | flex});
+  const ftxui::Component root = Vertical({row1 | flex, row2 | size(HEIGHT, EQUAL, 6)});
   screen_->loop(root);
 }
 
diff --git a/src/ui/helpers.h b/src/ui/helpers.h
@@ -27,6 +27,13 @@ class Helpers {
   static std::string Pad(const uint64_t input, const size_t width) {
     return Pad(std::to_string(input), width);
   }
+
+  // Helper to pad or truncate a std::array<char, 16> to a fixed width
+  static std::string Pad(const std::array<char, 16>& input, const size_t width) {
+    // Convert array to string (stop at null terminator if present)
+    std::string str(input.data());
+    return Pad(str, width);
+  }
 };
 
 }  // namespace ui
diff --git a/src/ui/log_box/log_box.h b/src/ui/log_box/log_box.h
@@ -8,6 +8,7 @@
 #include <mutex>
 #include <vector>
 
+#include "../../utils/env.h"
 #include "../app/iscreen.h"
 #include "ilog_watcher.h"
 #include "log_file_watcher.h"
@@ -38,8 +39,8 @@ class LogBox {
 
   // log ring-buffer
   std::deque<std::string> log_ring_;
-  static constexpr uint16_t MAX_LINES_ = 100;
-  std::mutex log_ring_mutex_;
+  static inline constexpr uint16_t MAX_LINES_ = 100;
+  alignas(utils::Env::CACHE_LINE_SIZE) std::mutex log_ring_mutex_;
 
   // log-file watcher
   std::unique_ptr<ILogWatcher> log_watcher_;
diff --git a/src/ui/log_box/log_file_watcher.h b/src/ui/log_box/log_file_watcher.h
@@ -15,7 +15,7 @@ class LogFileWatcher : public ILogWatcher, public efsw::FileWatchListener {
   using Callback = std::function<void(std::vector<std::string>)>;
 
  public:
-  static constexpr std::string THREAD_NAME_ = "tradercppuiLOG";
+  static inline constexpr std::string THREAD_NAME_ = "tradercppuiLOG";
 
   explicit LogFileWatcher(std::string directory, std::string filename)
       : directory_(directory), filename_(filename) {
diff --git a/src/ui/order_book_box.h b/src/ui/order_book_box.h
@@ -16,7 +16,7 @@ namespace ui {
 
 class OrderBookBox {
  public:
-  static constexpr std::string THREAD_NAME_ = "tradercppuiBOOK";
+  static inline constexpr std::string THREAD_NAME_ = "tradercppuiBOOK";
   // Constructor: takes a label string
   OrderBookBox(IScreen& screen,
                moodycamel::ConcurrentQueue<std::shared_ptr<const FIX44::Message>>& queue,
diff --git a/src/ui/trade_box.cpp b/src/ui/trade_box.cpp
@@ -247,17 +247,20 @@ void TradeBox::on_trade(const FIX44::MarketDataIncrementalRefresh& msg) {
               binance_config_.get_size_ticks_per_unit(symbol.value()));
           group.getField(trade_id);
           trade_id_str = trade_id.getValue();
-          std::string timeOnly = "";
-          if (group.isSetField(FIX::FIELD::TransactTime)) {
-            FIX::TransactTime transactTime;
-            group.getField(transactTime);
-            raw_time = transactTime.getString();
-            time_only = raw_time.substr(raw_time.find('-') + 1);
-          }
           std::from_chars(trade_id_str.data(), trade_id_str.data() + trade_id_str.size(),
                           trade_id_uint);
 
-          trade_ring_.push_back({time_only, side, price, size, trade_id_uint});
+          std::array<char, 16> tm_arr = {};
+          if (group.isSetField(FIX::FIELD::TransactTime)) {
+            group.getField(time);
+            FIX::UtcTimeStamp tval = time.getValue();
+            int microseconds = tval.getMillisecond() * 1000;
+            std::snprintf(tm_arr.data(), tm_arr.size(), "%02d:%02d:%02d.%06d",
+                          tval.getHour(), tval.getMinute(), tval.getSecond(),
+                          microseconds);
+          }
+
+          trade_ring_.push_back(core::Trade(side, price, size, trade_id_uint, tm_arr));
           screen_.post_event(ftxui::Event::Custom);
         } else {
           spdlog::error("trade with no side. message [{}]", msg.toString());
diff --git a/src/ui/trade_box.h b/src/ui/trade_box.h
@@ -10,6 +10,7 @@
 
 #include "../binance/config.h"
 #include "../core/trade.h"
+#include "../utils/env.h"
 #include "app/iscreen.h"
 #include "concurrentqueue.h"
 
@@ -23,7 +24,7 @@ namespace ui {
 
 class TradeBox {
  public:
-  static constexpr std::string THREAD_NAME_ = "tradercppuiTX";
+  static inline constexpr std::string THREAD_NAME_ = "tradercppuiTX";
   TradeBox(IScreen& screen,
            binance::Config& binance_config,
            moodycamel::ConcurrentQueue<std::shared_ptr<const FIX44::Message>>& queue,
@@ -49,9 +50,9 @@ class TradeBox {
   binance::Config& binance_config_;
 
   // trade ring-buffer stuff
-  static constexpr u_int16_t MAX_LINES_ = 100;
+  static inline constexpr u_int16_t MAX_LINES_ = 100;
   boost::circular_buffer<core::Trade> trade_ring_;
-  std::mutex trade_ring_mutex_;
+  alignas(utils::Env::CACHE_LINE_SIZE) std::mutex trade_ring_mutex_;
 
   // worker thread stuff
   // queue of order messages from FIX thread
diff --git a/src/utils/double.h b/src/utils/double.h
@@ -14,7 +14,7 @@ struct Double {
   /// @param value The double to convert to an int.
   /// NB: the max integer represented by a double is 2^53 (i.e. less than 2^64).
   /// @param ticks_per_unit the multiplier to apply. typically 1/tick_size.
-  inline static uint64_t toUint64(const double value, const double ticks_per_unit) {
+  static inline uint64_t toUint64(const double value, const double ticks_per_unit) {
     const double scaled = value * ticks_per_unit;
     return static_cast<uint64_t>(scaled);
   }
diff --git a/src/utils/env.h b/src/utils/env.h
@@ -4,6 +4,8 @@
 #include <stdexcept>
 #include <string>
 
+#include "spdlog/spdlog.h"
+
 namespace utils {
 
 struct Env {
@@ -20,6 +22,46 @@ struct Env {
     }
     throw std::runtime_error(std::format("envvar not defined, key [{}]", key));
   };
+
+  /// @brief log the architecutre in use
+  static void log_arch() {
+    // detect architecture
+#if defined(__aarch64__) || defined(_M_ARM64)
+    constexpr const char* ARCH = "ARM64";
+#elif defined(__arm__) || defined(_M_ARM)
+    constexpr const char* ARCH = "ARM (32-bit)";
+#elif defined(__x86_64__) || defined(_M_X64)
+    constexpr const char* ARCH = "x86_64";
+#elif defined(__i386__) || defined(_M_IX86)
+    constexpr const char* ARCH = "x86 (32-bit)";
+#else
+    constexpr const char* ARCH = "unknown architecture";
+#endif
+
+    // detect OS
+#if defined(_WIN32)
+    constexpr const char* OS = "windows";
+#elif defined(__APPLE__)
+    constexpr const char* OS = "macOS";
+#elif defined(__linux__)
+    constexpr const char* OS = "linux";
+#else
+    constexpr const char* OS = "unknown OS";
+#endif
+
+    // log combined info
+    spdlog::info("Compiled for {} on {}", ARCH, OS);
+  }
+
+  /// @brief Cache line size for the current architecture
+  static inline constexpr std::size_t CACHE_LINE_SIZE =
+#if defined(__aarch64__) || defined(_M_ARM64)
+      128;
+#elif defined(__x86_64__) || defined(_M_X64)
+      64;
+#else
+      64;  // default/fallback cache line size
+#endif
 };
 
 }  // namespace utils
diff --git a/src/utils/threading.h b/src/utils/threading.h
@@ -22,7 +22,7 @@ class Threading {
   /// in its default logging pattern (`%t`).
   /// @return A platform-specific thread identifier as an unsigned 64-bit integer.
   static uint64_t get_os_thread_id();
-  static constexpr uint64_t ERROR_THREAD_ID = 9999999;
+  static inline constexpr uint64_t ERROR_THREAD_ID = 9999999;
 };
 
 }  // namespace utils

Original file line number	Diff line number	Diff line change
`@@ -77,7 +77,7 @@ void App::start() {`
`77`	`77`	`const ftxui::Component row2 =`
`78`	`78`	`Horizontal({Vertical({wallet_box_.get_component() \| flex}) \| flex,`
`79`	`79`	`Vertical({log_box_->get_component() \| flex}) \| flex});`
`80`		`- const ftxui::Component root = Vertical({row1 \| size(HEIGHT, EQUAL, 20), row2 \| flex});`
	`80`	`+ const ftxui::Component root = Vertical({row1 \| flex, row2 \| size(HEIGHT, EQUAL, 6)});`
`81`	`81`	`screen_->loop(root);`
`82`	`82`	`}`
`83`	`83`