ci(perf): optimize the schedule (OpenXiangShan#3798)

1. Use a conditional step after the schedule to ensure strict biweekly
execution.
2. Allow specifying a commit SHA for manual runs.
3. Retain each test's emu; if an emu exists, skip the build. This
approach both preserves the emu for reproducibility and saves build
time.

.github/workflows/perf.yml

@@ -2,24 +2,60 @@ name: Performance Regression
 on:
   schedule:
     #run at 15:30 UTC (23:30 UTC+8) on Friday
-    # - cron: '30 15 * * 5'
+    - cron: '30 15 * * 5'
     #run at 15:30 UTC (23:30 UTC+8) Every two weeks
-    - cron: '30 15 13,27 * *'
+    # - cron: '30 15 13,27 * *'
   #run it manually when the workflow is in the default branch
   workflow_dispatch:
+    inputs:
+      test_commit:
+        description: 'Commit SHA to run the workflow on'
+        required: false
+        default: ''
+  #only for test push
+  # push:
+  #   branches: [ ci-perf-yml ]
+
 
 jobs:
   run:
     runs-on: perf
     continue-on-error: false
     #At most 2 days to finish
     timeout-minutes: 2880
-    name: Performance Regression - Checkpoints
+    name: Checkpoints
     steps:
-      - uses: actions/checkout@v2
+      - name: Set test commit
+        id: set_test_commit
+        run: |
+          if [ "${{ github.event.inputs.test_commit }}" = "" ]; then
+            echo "Using latest commit."
+            echo "commit_sha=${{ github.sha }}" >> $GITHUB_OUTPUT
+          else
+            echo "Using specified commit: ${{ github.event.inputs.test_commit }}"
+            echo "commit_sha=${{ github.event.inputs.test_commit }}" >> $GITHUB_OUTPUT
+          fi
+
+      - name: Determine if this is the biweekly run
+        id: determine_run
+        run: |
+          if [ "${{ github.event_name }}" = "workflow_dispatch" ]; then
+            echo "run_biweekly=true" >> $GITHUB_OUTPUT
+          elif [ $(( $(date +'%V') % 2 )) -eq 1 ]; then
+            echo "run_biweekly=true" >> $GITHUB_OUTPUT
+          else
+            echo "run_biweekly=false" >> $GITHUB_OUTPUT
+          fi
+
+      - name: Checkout code at specific commit
+        if: steps.determine_run.outputs.run_biweekly == 'true'
+        uses: actions/checkout@v2
         with:
+          ref: ${{ steps.set_test_commit.outputs.commit_sha }}
           submodules: 'recursive'
+
       - name: Set env
+        if: steps.determine_run.outputs.run_biweekly == 'true'
         run: |
           SHORT_SHA=$(git rev-parse --short HEAD)
           DATE=$(git show -s --format=%cd --date=format:%y%m%d HEAD)  
@@ -30,24 +66,39 @@ jobs:
           echo "SPEC_DIR=/nfs/home/ci-runner/master-perf-report/cr${DATE}-${SHORT_SHA}" >> $GITHUB_ENV
           echo "CKPT_HOME=/nfs/home/share/checkpoints_profiles/spec06_rv64gcb_O3_20m_gcc12.2.0-intFpcOff-jeMalloc/checkpoint-0-0-0" >> $GITHUB_ENV
           echo "CKPT_JSON_PATH=/nfs/home/share/checkpoints_profiles/spec06_rv64gcb_O3_20m_gcc12.2.0-intFpcOff-jeMalloc/checkpoint-0-0-0/cluster-0-0.json" >> $GITHUB_ENV
-      - name: Clean up
+
+      - name: Clean Up
+        if: steps.determine_run.outputs.run_biweekly == 'true'
         run: |
           python3 $GITHUB_WORKSPACE/scripts/xiangshan.py --clean
+
       - name: Build EMU with DRAMsim3
+        if: steps.determine_run.outputs.run_biweekly == 'true'
         run: |
-          python3 $GITHUB_WORKSPACE/scripts/xiangshan.py --build          \
-            --dramsim3 /nfs/home/share/ci-workloads/DRAMsim3              \
-            --with-dramsim3 --threads 16                                  \
-            --pgo $GITHUB_WORKSPACE/ready-to-run/coremark-2-iteration.bin \
-            --llvm-profdata llvm-profdata
+          if [ -e "$SPEC_DIR/emu" ]; then
+            mkdir -p $NOOP_HOME/build
+            cp $SPEC_DIR/emu $NOOP_HOME/build/emu
+          else
+            python3 $GITHUB_WORKSPACE/scripts/xiangshan.py --build          \
+              --dramsim3 /nfs/home/share/ci-workloads/DRAMsim3              \
+              --with-dramsim3 --threads 16                                  \
+              --pgo $GITHUB_WORKSPACE/ready-to-run/coremark-2-iteration.bin \
+              --llvm-profdata llvm-profdata
+            mkdir -p $SPEC_DIR
+            cp $NOOP_HOME/build/emu $SPEC_DIR/emu
+          fi
+
       - name: Run SPEC CPU2006 checkpoints
+        if: steps.determine_run.outputs.run_biweekly == 'true'
         run: |
           cd $PERF_HOME
           python3 xs_autorun_multiServer.py $CKPT_HOME $CKPT_JSON_PATH \
             --xs $NOOP_HOME --threads 16 --dir $SPEC_DIR --resume \
             -L "node033 node034 node036 node037 node038 node039 node040 node041 node042"
           find $NOOP_HOME/build/ -maxdepth 1 -name "*.vcd" -exec mv {} $SPEC_DIR \;
+
       - name: Report SPEC CPU2006 score
+        if: steps.determine_run.outputs.run_biweekly == 'true'
         run: |
           cd $PERF_HOME
           python3 xs_autorun_multiServer.py $CKPT_HOME $CKPT_JSON_PATH \
@@ -59,7 +110,9 @@ jobs:
           mkdir $GITHUB_WORKSPACE/result
           cp $SPEC_DIR/err_ckps.json $GITHUB_WORKSPACE/result/err_ckps.json
           cp $SPEC_DIR/score.txt $GITHUB_WORKSPACE/result/score.txt
+
       - name: Upload result
+        if: steps.determine_run.outputs.run_biweekly == 'true'
         uses: actions/upload-artifact@v4
         with:
           name: result