Add benchmark trend reporting with benchstat baseline

Author: sidmohan0

.github/workflows/main-cicd.yml

@@ -50,15 +50,16 @@ jobs:
         uses: actions/setup-go@v5
         with:
           go-version: "1.24.13"
-      - name: Run benchmark suites
+      - name: Run benchmark suites with trend report
         run: |
-          mkdir -p /tmp/bench
-          go test -run '^$' -bench "BenchmarkScanText|BenchmarkPolicyEvaluate|BenchmarkDecideEndpoint|BenchmarkScanEndpoint" -benchmem ./internal/scan ./internal/policy ./internal/server | tee /tmp/bench/benchmark.txt
-      - name: Upload benchmark artifact
+          bash scripts/run-benchmarks.sh
+      - name: Upload benchmark artifacts
         uses: actions/upload-artifact@v4
         with:
           name: benchmark-results
-          path: /tmp/bench/benchmark.txt
+          path: |
+            /tmp/bench/benchmark-current.txt
+            /tmp/bench/benchmark-trend.txt
 
   race:
     runs-on: ubuntu-latest

README.md

@@ -379,4 +379,4 @@ spec:
 4. Environment variables are set and files are writable
 5. API token/header if `DATAFOG_API_TOKEN` is configured
 6. Policy JSON is valid and rules match expected action fields
-7. Optional benchmark sweep: `scripts/run-benchmarks.sh`
+7. Optional benchmark sweep: `scripts/run-benchmarks.sh` (writes `/tmp/bench/benchmark-current.txt`; if `scripts/benchmark-baseline.txt` exists, also writes `/tmp/bench/benchmark-trend.txt` with benchstat deltas)

scripts/benchmark-baseline.txt

@@ -0,0 +1,26 @@
+goos: darwin
+goarch: arm64
+pkg: github.com/datafog/datafog-api/internal/scan
+cpu: Apple M3
+BenchmarkScanTextSmall-8        	   64513	     16559 ns/op	   3.62 MB/s	    6881 B/op	      51 allocs/op
+BenchmarkScanTextMedium-8       	   38298	     30559 ns/op	   3.99 MB/s	   12209 B/op	      54 allocs/op
+BenchmarkScanTextLarge-8        	    6988	    170732 ns/op	   2.88 MB/s	  158424 B/op	     193 allocs/op
+BenchmarkScanTextWithFilter-8   	  144634	      8321 ns/op	  14.66 MB/s	    1444 B/op	      12 allocs/op
+PASS
+ok  	github.com/datafog/datafog-api/internal/scan	5.508s
+goos: darwin
+goarch: arm64
+pkg: github.com/datafog/datafog-api/internal/policy
+cpu: Apple M3
+BenchmarkPolicyEvaluateSorted-8     	 7168506	       154.2 ns/op	      16 B/op	       1 allocs/op
+BenchmarkPolicyEvaluateUnsorted-8   	 2565021	       470.7 ns/op	    2136 B/op	       5 allocs/op
+PASS
+ok  	github.com/datafog/datafog-api/internal/policy	3.144s
+goos: darwin
+goarch: arm64
+pkg: github.com/datafog/datafog-api/internal/server
+cpu: Apple M3
+BenchmarkScanEndpoint-8     	   58554	     19254 ns/op	   3.38 MB/s	   15734 B/op	      99 allocs/op
+BenchmarkDecideEndpoint-8   	     405	   2923160 ns/op	   0.03 MB/s	   11742 B/op	      67 allocs/op
+PASS
+ok  	github.com/datafog/datafog-api/internal/server	3.022s

scripts/run-benchmarks.sh

@@ -2,8 +2,42 @@
 
 set -euo pipefail
 
+BENCH_PATTERN='BenchmarkScanText|BenchmarkPolicyEvaluate|BenchmarkDecideEndpoint|BenchmarkScanEndpoint'
+OUTPUT_DIR="${DATAFOG_BENCH_OUTPUT_DIR:-/tmp/bench}"
+CURRENT_FILE="${DATAFOG_BENCH_CURRENT_FILE:-$OUTPUT_DIR/benchmark-current.txt}"
+TREND_FILE="${DATAFOG_BENCH_TREND_FILE:-$OUTPUT_DIR/benchmark-trend.txt}"
+BASELINE_FILE="${DATAFOG_BENCH_BASELINE_FILE:-$(pwd)/scripts/benchmark-baseline.txt}"
+
+mkdir -p "$OUTPUT_DIR"
+
 echo "Running API hot-path benchmark suite..."
+go test -run '^$' -bench "$BENCH_PATTERN" -benchmem ./internal/scan ./internal/policy ./internal/server | tee "$CURRENT_FILE"
+
+echo "Benchmark output written to $CURRENT_FILE"
+
+if [ -f "$BASELINE_FILE" ]; then
+  echo "Comparing against baseline: $BASELINE_FILE"
+
+  BENCHSTAT_BIN=""
+  if command -v benchstat >/dev/null 2>&1; then
+    BENCHSTAT_BIN="$(command -v benchstat)"
+  else
+    if ! go install golang.org/x/perf/cmd/benchstat@latest >/dev/null; then
+      echo "warn: unable to install benchstat; skipping trend report"
+      exit 0
+    fi
 
-go test -run '^$' -bench 'BenchmarkScanText|BenchmarkPolicyEvaluate|BenchmarkDecideEndpoint|BenchmarkScanEndpoint' -benchmem ./internal/scan ./internal/policy ./internal/server | tee /tmp/benchmark-results.txt
+    GO_BIN="$(go env GOPATH)/bin/benchstat"
+    if [ -x "$GO_BIN" ]; then
+      BENCHSTAT_BIN="$GO_BIN"
+    else
+      echo "warn: benchstat not available after installation; skipping trend report"
+      exit 0
+    fi
+  fi
 
-echo "Benchmark output written to /tmp/benchmark-results.txt"
+  "$BENCHSTAT_BIN" "$BASELINE_FILE" "$CURRENT_FILE" | tee "$TREND_FILE"
+  echo "Trend report written to $TREND_FILE"
+else
+  echo "No baseline found at $BASELINE_FILE, skipping trend comparison"
+fi