build: auto-set GitHub runner make job count

.github/actions/set-make-job-count/action.yml

@@ -0,0 +1,22 @@
+name: 'set-make-job-count'
+description: 'Set the MAKE_JOB_COUNT environment variable to a value suitable for the host runner'
+runs:
+  using: "composite"
+  steps:
+    # Each job runner requires 2.25 GiB (i.e. 1024 * 9/4 MiB) memory and
+    # a dedicated logical CPU core
+    - name: set-jobs-macOS
+      if: runner.os == 'macOS'
+      run: |
+        echo MAKE_JOB_COUNT=$(expr $(printf '%s\n%s' $(( $(sysctl -n hw.memsize) * 4 / (1073741824 * 9) )) $(sysctl -n hw.logicalcpu) | sort -n | head -n1) '|' 1) >> $GITHUB_ENV
+      shell: bash
+    - name: set-jobs-windows
+      if: runner.os == 'Windows'
+      run: |
+        echo MAKE_JOB_COUNT=$(expr $(printf '%s\n%s' $(( $(grep MemTotal: /proc/meminfo | cut -d: -f2 | cut -dk -f1) * 4 / (1048576 * 9) )) $(nproc) | sort -n | head -n1) '|' 1) >> $GITHUB_ENV
+      shell: msys2 {0}
+    - name: set-jobs-linux
+      if: runner.os == 'Linux'
+      run: |
+        echo MAKE_JOB_COUNT=$(expr $(printf '%s\n%s' $(( $(grep MemTotal: /proc/meminfo | cut -d: -f2 | cut -dk -f1) * 4 / (1048576 * 9) )) $(nproc) | sort -n | head -n1) '|' 1) >> $GITHUB_ENV
+      shell: bash

.github/workflows/build.yml

@@ -13,8 +13,7 @@ on:
 # The below variables reduce repetitions across similar targets
 env:
   REMOVE_BUNDLED_PACKAGES : sudo rm -rf /usr/local
-  BUILD_DEFAULT_LINUX: |
-        cmake -S . -B build -D ARCH="default" -D BUILD_TESTS=ON -D CMAKE_BUILD_TYPE=Release && cmake --build build --parallel 4
+  BUILD_DEFAULT_LINUX: 'cmake -S . -B build -D ARCH="default" -D BUILD_TESTS=ON -D CMAKE_BUILD_TYPE=Release && cmake --build build'
   APT_INSTALL_LINUX: 'apt -y install build-essential cmake libboost-all-dev miniupnpc libunbound-dev graphviz doxygen libunwind8-dev pkg-config libssl-dev libzmq3-dev libsodium-dev libhidapi-dev libusb-1.0-0-dev libprotobuf-dev protobuf-compiler ccache git'
   APT_SET_CONF: |
         tee -a /etc/apt/apt.conf.d/80-custom << EOF
@@ -42,14 +41,15 @@ jobs:
         path: /Users/runner/Library/Caches/ccache
         key: ccache-${{ runner.os }}-build-${{ github.sha }}
         restore-keys: ccache-${{ runner.os }}-build-
+    - uses: ./.github/actions/set-make-job-count
     - name: install dependencies
       run: |
         HOMEBREW_NO_AUTO_UPDATE=1 brew install boost hidapi openssl zmq miniupnpc expat libunwind-headers protobuf@21 ccache
         brew link protobuf@21 boost
     - name: build
       run: |
         ${{env.CCACHE_SETTINGS}}
-        make -j3
+        make -j${{env.MAKE_JOB_COUNT}}
 
   build-windows:
     name: 'Windows (MSYS2)'
@@ -73,10 +73,11 @@ jobs:
       with:
         update: true
         install: mingw-w64-x86_64-toolchain make mingw-w64-x86_64-cmake mingw-w64-x86_64-ccache mingw-w64-x86_64-boost mingw-w64-x86_64-openssl mingw-w64-x86_64-zeromq mingw-w64-x86_64-libsodium mingw-w64-x86_64-hidapi mingw-w64-x86_64-protobuf mingw-w64-x86_64-libusb mingw-w64-x86_64-unbound git pkg-config
+    - uses: ./.github/actions/set-make-job-count
     - name: build
       run: |
         ${{env.CCACHE_SETTINGS}}
-        make release-static-win64 -j4
+        make release-static-win64 -j${{env.MAKE_JOB_COUNT}}
 
   build-debian:
     name: 'Debian 10'
@@ -97,8 +98,9 @@ jobs:
       - uses: actions/checkout@v4
         with:
           submodules: recursive
+      - uses: ./.github/actions/set-make-job-count
       - name: build
-        run: ${{env.BUILD_DEFAULT_LINUX}}
+        run: ${{env.BUILD_DEFAULT_LINUX}} --parallel ${{env.MAKE_JOB_COUNT}}
 
 # See the OS labels and monitor deprecations here:
 # https://docs.github.com/en/actions/using-github-hosted-runners/about-github-hosted-runners#supported-runners-and-hardware-resources
@@ -125,6 +127,7 @@ jobs:
         path: ~/.ccache
         key: ccache-${{ runner.os }}-build-${{ matrix.os }}-${{ github.sha }}
         restore-keys: ccache-${{ runner.os }}-build-${{ matrix.os }}
+    - uses: ./.github/actions/set-make-job-count
     - name: remove bundled packages
       run: ${{env.REMOVE_BUNDLED_PACKAGES}}
     - name: set apt conf
@@ -136,7 +139,7 @@ jobs:
     - name: build
       run: |
         ${{env.CCACHE_SETTINGS}}
-        ${{env.BUILD_DEFAULT_LINUX}}
+        ${{env.BUILD_DEFAULT_LINUX}} --parallel ${{env.MAKE_JOB_COUNT}}
 
   libwallet-ubuntu:
     name: "Ubuntu 20.04 (libwallet)"
@@ -152,6 +155,7 @@ jobs:
         path: ~/.ccache
         key: ccache-${{ runner.os }}-libwallet-${{ github.sha }}
         restore-keys: ccache-${{ runner.os }}-libwallet-
+    - uses: ./.github/actions/set-make-job-count
     - name: remove bundled packages
       run: ${{env.REMOVE_BUNDLED_PACKAGES}}
     - name: set apt conf
@@ -164,7 +168,7 @@ jobs:
       run: |
         ${{env.CCACHE_SETTINGS}}
         cmake .
-        make wallet_api -j4
+        make wallet_api -j${{env.MAKE_JOB_COUNT}}
 
   test-ubuntu:
     name: "Ubuntu 20.04 (tests)"
@@ -182,6 +186,7 @@ jobs:
         path: ~/.ccache
         key: ccache-${{ runner.os }}-build-ubuntu-latest-${{ github.sha }}
         restore-keys: ccache-${{ runner.os }}-build-ubuntu-latest
+    - uses: ./.github/actions/set-make-job-count
     - name: remove bundled packages
       run: ${{env.REMOVE_BUNDLED_PACKAGES}}
     - name: set apt conf
@@ -198,7 +203,7 @@ jobs:
         DNS_PUBLIC: tcp://9.9.9.9
       run: |
         ${{env.CCACHE_SETTINGS}}
-        ${{env.BUILD_DEFAULT_LINUX}}
+        ${{env.BUILD_DEFAULT_LINUX}} --parallel ${{env.MAKE_JOB_COUNT}}
         cmake --build build --target test
 
 # ARCH="default" (not "native") ensures, that a different execution host can execute binaries compiled elsewhere.

.github/workflows/depends.yml

@@ -79,6 +79,7 @@ jobs:
         restore-keys: |
           depends-${{ matrix.toolchain.host }}-${{ hashFiles('contrib/depends/packages/*') }}
           depends-${{ matrix.toolchain.host }}-
+    - uses: ./.github/actions/set-make-job-count
     - name: set apt conf
       run: ${{env.APT_SET_CONF}}
     - name: install dependencies
@@ -91,7 +92,7 @@ jobs:
     - name: build
       run: |
         ${{env.CCACHE_SETTINGS}}
-        make depends target=${{ matrix.toolchain.host }} -j4
+        make depends target=${{ matrix.toolchain.host }} -j${{env.MAKE_JOB_COUNT}}
     - uses: actions/upload-artifact@v4
       if: ${{ matrix.toolchain.host == 'x86_64-w64-mingw32' || matrix.toolchain.host == 'x86_64-apple-darwin' || matrix.toolchain.host == 'aarch64-apple-darwin' || matrix.toolchain.host == 'x86_64-unknown-linux-gnu' }}
       with: