WIP.

Author: ixotoxin

.github/workflows/cmake-multi-platform.yml

@@ -1,5 +1,3 @@
-# This starter workflow is for a CMake project running on multiple platforms. There is a different starter workflow if you just want a single platform.
-# See: https://github.com/actions/starter-workflows/blob/main/ci/cmake-single-platform.yml
 name: Build and test on multiple platforms
 
 on:
@@ -14,15 +12,8 @@ jobs:
     runs-on: ${{ matrix.os }}
 
     strategy:
-      # Set fail-fast to false to ensure that feedback is delivered for all matrix combinations. Consider changing this to true when your workflow is stable.
       fail-fast: false
 
-      # Set up a matrix to run the following 3 configurations:
-      # 1. <Windows, Release, latest MSVC compiler toolchain on the default runner image, default generator>
-      # 2. <Linux, Release, latest GCC compiler toolchain on the default runner image, default generator>
-      # 3. <Linux, Release, latest Clang compiler toolchain on the default runner image, default generator>
-      #
-      # To add more build types (Release, Debug, RelWithDebInfo, etc.) customize the build_type list.
       matrix:
         os: [ubuntu-latest, windows-latest]
         build_type: [Debug]
@@ -61,15 +52,12 @@ jobs:
         git status
 
     - name: Set reusable strings
-      # Turn repeated input strings (such as the build output directory) into step outputs. These step outputs can be used throughout the workflow file.
       id: strings
       shell: bash
       run: |
         echo "build-output-dir=${{ github.workspace }}/build" >> "$GITHUB_OUTPUT"
 
     - name: Configure CMake
-      # Configure CMake in a 'build' subdirectory. `CMAKE_BUILD_TYPE` is only required if you are using a single-configuration generator such as make.
-      # See https://cmake.org/cmake/help/latest/variable/CMAKE_BUILD_TYPE.html?highlight=cmake_build_type
       run: >
         cmake -B ${{ steps.strings.outputs.build-output-dir }}
         -DCMAKE_CXX_COMPILER=${{ matrix.cpp_compiler }}
@@ -79,11 +67,8 @@ jobs:
         -S ${{ github.workspace }}
 
     - name: Build
-      # Build your program with the given configuration. Note that --config is needed because the default Windows generator is a multi-config generator (Visual Studio generator).
       run: cmake --build ${{ steps.strings.outputs.build-output-dir }} --config ${{ matrix.build_type }}
 
     - name: Test
       working-directory: ${{ steps.strings.outputs.build-output-dir }}
-      # Execute tests defined by the CMake configuration. Note that --build-config is needed because the default Windows generator is a multi-config generator (Visual Studio generator).
-      # See https://cmake.org/cmake/help/latest/manual/ctest.1.html for more detail
-      run: ctest --build-config ${{ matrix.build_type }}
+      run: ctest --rerun-failed --output-on-failure --build-config ${{ matrix.build_type }}

include/xtxn/alignment.hpp

@@ -0,0 +1,14 @@
+// Copyright (c) 2025 Vitaly Anasenko
+// Distributed under the MIT License, see accompanying file LICENSE.txt
+
+#pragma once
+
+#include <new>
+
+namespace xtxn {
+#ifdef __cpp_lib_hardware_interference_size
+    constexpr std::size_t queue_alignment { std::hardware_constructive_interference_size };
+#else
+    constexpr std::size_t queue_alignment { 64 };
+#endif
+}

include/xtxn/fast_mpmc_queue.hpp

@@ -5,11 +5,11 @@
 
 #include <cassert>
 #include <concepts>
-#include <new>
 #include <atomic>
 #include <array>
 #include "fast_queue_internal.hpp"
 #include "spinlock.hpp"
+#include "alignment.hpp"
 
 namespace xtxn {
     enum class queue_growth_policy { call, round, step };
@@ -23,7 +23,7 @@ namespace xtxn {
         queue_growth_policy G = queue_growth_policy::round
     >
     requires ((S >= 4) && (L <= queue_max_capacity_limit) && (S <= L) && (A > 0) && (A <= queue_max_attempts))
-    class alignas(std::hardware_constructive_interference_size) fast_mpmc_queue {
+    class alignas(queue_alignment) fast_mpmc_queue {
         struct slot;
         struct block;
         using slot_completion = queue_slot_completion<C>;

include/xtxn/fastest_mpmc_queue.hpp

@@ -5,10 +5,10 @@
 
 #include <cassert>
 #include <concepts>
-#include <new>
 #include <atomic>
 #include <array>
 #include "fast_queue_internal.hpp"
+#include "alignment.hpp"
 
 namespace xtxn {
     template<
@@ -18,7 +18,7 @@ namespace xtxn {
         int32_t A = queue_default_attempts
     >
     requires ((S >= 4) && (S <= queue_max_capacity_limit) && (A > 0) && (A <= queue_max_attempts))
-    class alignas(std::hardware_constructive_interference_size) fastest_mpmc_queue {
+    class alignas(queue_alignment) fastest_mpmc_queue {
         struct slot;
         using slot_completion = queue_slot_completion<C>;
         // class base_accessor;

include/xtxn/mpmc_queue.hpp

@@ -10,12 +10,12 @@
 
 #include <cassert>
 #include <cstdint>
-#include <new>
 #include <atomic>
 #include <memory>
 #include <unordered_map>
 #include <algorithm>
 #include "spinlock.hpp"
+#include "alignment.hpp"
 
 namespace xtxn {
     constexpr int64_t queue_default_purge_counter { 0x80 };
@@ -29,7 +29,7 @@ namespace xtxn {
         int S = queue_default_purge_skip_first
     >
     requires (C >= 4) && (S >= 4)
-    class alignas(std::hardware_constructive_interference_size) mpmc_queue final {
+    class alignas(queue_alignment) mpmc_queue final {
         struct node;
         using mo = std::memory_order;
         using epoch_type = uint_fast64_t;

include/xtxn/mpmcdd_queue.hpp

@@ -7,14 +7,14 @@
 
 #pragma once
 
-#include <new>
 #include <atomic>
 #include <memory>
 #include "color_barrier.hpp"
+#include "alignment.hpp"
 
 namespace xtxn {
     template<typename T>
-    class alignas(std::hardware_constructive_interference_size) mpmcdd_queue final {
+    class alignas(queue_alignment) mpmcdd_queue final {
         struct node;
         using mo = std::memory_order;
 

include/xtxn/mpmcsl_queue.hpp

@@ -7,14 +7,14 @@
 
 #pragma once
 
-#include <new>
 #include <atomic>
 #include <memory>
 #include "spinlock.hpp"
+#include "alignment.hpp"
 
 namespace xtxn {
     template<typename T>
-    class alignas(std::hardware_constructive_interference_size) mpmcsl_queue final {
+    class alignas(queue_alignment) mpmcsl_queue final {
         struct node;
         using mo = std::memory_order;
 

include/xtxn/mpsc_queue.hpp

@@ -3,13 +3,13 @@
 
 #pragma once
 
-#include <new>
 #include <atomic>
 #include <memory>
+#include "alignment.hpp"
 
 namespace xtxn {
     template<typename T>
-    class alignas(std::hardware_constructive_interference_size) mpsc_queue final {
+    class alignas(queue_alignment) mpsc_queue final {
         struct node;
         using mo = std::memory_order;