Expand regression CI to run multiple network topologies via matrix strategy

Author: shashankov

.github/workflows/ci.yml

@@ -7,24 +7,13 @@ on:
     branches: [ main ]
 
 jobs:
-  regress:
-    name: Verilator Regression Suite
+  setup-verilator:
+    name: Setup Verilator Cache
     runs-on: ubuntu-latest
-
     steps:
       - name: Checkout Code
         uses: actions/checkout@v5
 
-      - name: Set up Python
-        uses: actions/setup-python@v5
-        with:
-          python-version: '3.x'
-
-      - name: Install Python Dependencies
-        run: |
-          python -m pip install --upgrade pip
-          pip install numpy
-
       - name: Cache Verilator Build
         id: cache-verilator
         uses: actions/cache@v5
@@ -33,6 +22,7 @@ jobs:
           key: verilator-5.048-v2
 
       - name: Install Build Prerequisites
+        if: steps.cache-verilator.outputs.cache-hit != 'true'
         run: |
           sudo apt-get update
           sudo apt-get install -y git help2man perl python3 make autoconf g++ flex bison ccache
@@ -53,10 +43,58 @@ jobs:
           make -j$(nproc)
           make install
 
+  regress:
+    name: Regression / ${{ matrix.config }}
+    needs: setup-verilator
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        config:
+          - router_4x4
+          - router_8x8
+          - ring_4
+          - ring_8
+          - double_ring_4
+          - mesh_2x2
+          - mesh_4x4
+          - torus_2x2
+          - torus_4x4
+          - dtorus_2x2
+          - butterfly_k2_n2
+          - butterfly_k4_n2
+          - fat_tree_k2_n2
+          - fat_tree_k4_n2
+          - router_4x4_ser2
+          - router_4x4_clkcross2
+          - fully_connected_4x2
+
+    steps:
+      - name: Checkout Code
+        uses: actions/checkout@v5
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: '3.x'
+
+      - name: Install Python Dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install numpy
+
+      - name: Restore Verilator Cache
+        uses: actions/cache/restore@v5
+        with:
+          path: /home/runner/verilator-bin
+          key: verilator-5.048-v2
+          fail-on-cache-miss: true
+
       - name: Add Verilator to PATH
         run: |
           echo "/home/runner/verilator-bin/bin" >> $GITHUB_PATH
 
       - name: Run Regression Suite
         run: |
-          make -C test regress REGRESS_PACKET_COUNT=65536 THREADS=4
+          ARGS=$(make -C test --no-print-directory _regress_print_args_${{ matrix.config }})
+          make -C test verilator $ARGS PACKET_COUNT=65536 THREADS=4