initial commit

.github/workflows/main.yaml

@@ -0,0 +1,52 @@
+name: Main
+on:
+  push:
+    branches:
+      - main
+
+permissions:
+  contents: read
+
+jobs:
+  go-bench:
+    runs-on: ubuntu-latest
+    timeout-minutes: 15
+    steps:
+      - uses: actions/checkout@8ade135a41bc03ea155e62e844d188df1ea18608 # v3.5.2
+
+      - uses: actions/setup-go@93397bea11091df50f3d7e59dc26a7711a8bcfbe # v4.1.0
+        with:
+          go-version-file: './go.mod'
+          cache-dependency-path: './go.sum'
+          check-latest: true
+
+      - name: Run benchmark
+        run: |
+          set -o pipefail
+          make bench | tee bench_output.txt
+
+      - name: Get JSON for benchmark
+        uses: benchmark-action/github-action-benchmark@70405016b032d44f409e4b1b451c40215cbe2393 # v1.18.0
+        with:
+          # What benchmark tool the output.txt came from
+          tool: 'go'
+          # Where the output from the benchmark tool is stored
+          output-file-path: bench_output.txt
+          # Updates the file content instead of generating a Git commit in GitHub Pages branch
+          external-data-json-path: ./cache/benchmark-data.json
+          # Workflow will fail when an alert happens
+          fail-on-alert: true
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          comment-on-alert: true
+
+      - name: Get CPU information
+        uses: kenchan0130/actions-system-info@master
+        id: system-info
+
+      - name: Save benchmark JSON
+        uses: actions/cache/save@704facf57e6136b1bc63b828d79edcd491f0ee84 # v3.3.2
+        with:
+          path: ./cache/benchmark-data.json
+          # Save with commit hash to avoid "cache already exists"
+          # Save with OS & CPU info to prevent comparing against results from different CPUs
+          key: ${{ github.sha }}-${{ runner.os }}-${{ steps.system-info.outputs.cpu-model }}-go-benchmark

.github/workflows/prs.yaml

@@ -0,0 +1,78 @@
+name: Pull Request
+on:
+  pull_request:
+    branches:
+      - main
+
+permissions:
+  contents: read
+
+jobs:
+  go-bench:
+    runs-on: ubuntu-latest
+    timeout-minutes: 15
+    steps:
+      - uses: actions/checkout@8ade135a41bc03ea155e62e844d188df1ea18608 # v3.5.2
+        with:
+          fetch-depth: 0
+
+      - uses: actions/setup-go@93397bea11091df50f3d7e59dc26a7711a8bcfbe # v4.1.0
+        with:
+          go-version-file: './go.mod'
+          cache-dependency-path: './go.sum'
+          check-latest: true
+
+      - name: Run benchmark on PR
+        run: |
+          set -o pipefail
+          make bench | tee ${{ github.sha }}_bench_output.txt
+
+      - name: Get CPU information
+        uses: kenchan0130/actions-system-info@master
+        id: system-info
+
+      - name: Get Main branch SHA
+        id: get-main-branch-sha
+        run: |
+          SHA=$(git rev-parse origin/main)
+          echo "sha=$SHA" >> $GITHUB_OUTPUT
+
+      - name: Download benchmark from Main
+        uses: actions/cache/restore@704facf57e6136b1bc63b828d79edcd491f0ee84 # v3.3.2
+        id: cache
+        with:
+          path: ./cache/benchmark-data.json
+          key: ${{ steps.get-main-branch-sha.outputs.sha }}-${{ runner.os }}-${{ steps.system-info.outputs.cpu-model }}-go-benchmark
+
+      - name: Compare benchmarks with Main
+        uses: benchmark-action/github-action-benchmark@v1
+        if: steps.cache.outputs.cache-hit == 'true'
+        with:
+          alert-threshold: "200%"
+          # What benchmark tool the output.txt came from
+          tool: 'go'
+          # Where the output from the benchmark tool is stored
+          output-file-path: ${{ github.sha }}_bench_output.txt
+          # Where the benchmarks in master are (to compare)
+          external-data-json-path: ./cache/benchmark-data.json
+          # Do not save the data
+          save-data-file: false
+          # Workflow will fail when an alert happens
+          fail-on-alert: true
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          # Enable Job Summary for PRs
+          summary-always: true
+
+      - name: Run benchmarks but don't compare to Main branch
+        uses: benchmark-action/github-action-benchmark@v1
+        if: steps.cache.outputs.cache-hit != 'true'
+        with:
+          # What benchmark tool the output.txt came from
+          tool: 'go'
+          # Where the output from the benchmark tool is stored
+          output-file-path: ${{ github.sha }}_bench_output.txt
+          # Write benchmarks to this file, do not publish to GitHub Pages
+          save-data-file: false
+          external-data-json-path: ./cache/benchmark-data.json
+          # Enable Job Summary for PRs
+          summary-always: true

Makefile

@@ -0,0 +1,9 @@
+.DEFAULT_GOAL := help
+
+.PHONY: help
+help:
+	@grep -E '^[a-zA-Z_-]+:.*?## .*$$' $(MAKEFILE_LIST) | sort | awk 'BEGIN {FS = ":.*?## "}; {printf "\033[36m%-30s\033[0m %s\n", $$1, $$2}'
+
+.PHONY: bench
+bench: ## Run benchmark test. See https://pkg.go.dev/cmd/go#hdr-Testing_flags
+	go test ./... -bench . -benchtime 5s -timeout 0 -run=XXX -cpu 1 -benchmem

README.md

@@ -0,0 +1,7 @@
+## Running benchmarks reliably with GitHub action
+
+This repo shows you can:
+
+1. run benchmarks for your Go code in the `main` branch and in PRs
+2. compare PR benchmarks against `main` benchmarks
+3. if no `main` benchmarks are available, just publish benchmarks in the summary of the PR

fib.go

@@ -1,8 +1,32 @@
 package fib
 
-func Fib(u uint) uint {
-	if u <= 1 {
+import (
+	"math/rand"
+	"sync"
+	"time"
+)
+
+var _m sync.Map
+
+// Fib returns nth Fibonnaci sequence number.
+func Fib(n uint) uint {
+	if n <= 1 {
 		return 1
 	}
-	return Fib(u-2) + Fib(u-1)
+
+	n2, ok := _m.Load(n - 2)
+	if !ok {
+		n2 = Fib(n - 2)
+		_m.Store(n-2, n2)
+	}
+	n1, ok := _m.Load(n - 1)
+	if !ok {
+		n1 = Fib(n - 1)
+		_m.Store(n-1, n1)
+	}
+
+	dur := 500*time.Microsecond + time.Duration(rand.Intn(500))*time.Microsecond
+	time.Sleep(dur)
+
+	return n2.(uint) + n1.(uint)
 }

fib_test.go

@@ -6,12 +6,18 @@ import (
 
 func BenchmarkFib10(b *testing.B) {
 	for i := 0; i < b.N; i++ {
-		_ = Fib(10)
+		_ = Fib(1)
 	}
 }
 
 func BenchmarkFib20(b *testing.B) {
 	for i := 0; i < b.N; i++ {
-		_ = Fib(20)
+		_ = Fib(1)
+	}
+}
+
+func BenchmarkFib25(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		_ = Fib(1)
 	}
 }