benchmarking Podman: proof of concept

Add a proof of concept for benchmarking Podman.  The benchmarks are
implemented by means of the end-to-end test suite but hidden behind
a `benchmarks` build tag.  Running `make localbenchmarks` will run
`test/e2e` with the specific build tag and set ginkgo's "focus" to
the specific "Podman Benchmark Suite" to only run this spec and skip
all others.

ginkgo will print a report before terminating listing the CPU and memory
stats for each benchmark.  New benchmarks can easily be added via the
`newBenchmark` function that also supports adding an `init()` function
to each benchmark which allows for performing certain setups for the
specific benchmark.  For instance, benchmarking `podman start` requires
creating a container beforehand.

Podman may be called more than once in the main function of a benchmark
but note that the displayed memory consumption is then a sum of all
Podman invocations.  The memory consumption is collected via
`/usr/bin/time`.

A benchmark's report is split into CPU and memory as displayed below:

```
[CPU] podman images:
  Fastest Time: 0.146s
  Slowest Time: 0.187s
  Average Time: 0.180s ± 0.015s
[MEM] podman images:
  Smallest: 41892.0KB
   Largest: 42792.0KB
   Average: 42380.7KB ± 286.4KB
```

Note that the benchmarks are not wired into the CI yet.  They are meant
as a proof of concept.  More benchmarks and the plumbing into CI will
happen in a later change.

Signed-off-by: Valentin Rothberg <vrothberg@redhat.com>

2 files changed, 186 insertions, 0 deletions

diff --git a/test/e2e/benchmarks_test.go b/test/e2e/benchmarks_test.go
new file mode 100644
index 000000000..c631b06ee
--- /dev/null
+++ b/test/e2e/benchmarks_test.go
@@ -0,0 +1,173 @@
+//go:build benchmarks
+// +build benchmarks
+
+package integration
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path"
+	"strconv"
+	"strings"
+
+	. "github.com/containers/podman/v4/test/utils"
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+	. "github.com/onsi/gomega/gexec"
+)
+
+var (
+	// Number of times to execute each benchmark.
+	numBenchmarkSamples = 3
+	// All benchmarks are ququed here.
+	allBenchmarks []benchmark
+)
+
+// An internal struct for queuing benchmarks.
+type benchmark struct {
+	// The name of the benchmark.
+	name string
+	// The function to execute.
+	main func()
+	// Function is run before `main`.
+	init func()
+}
+
+// Allows for customizing the benchnmark in an easy to extend way.
+type newBenchmarkOptions struct {
+	// Sets the benchmark's init function.
+	init func()
+}
+
+// Queue a new benchmark.
+func newBenchmark(name string, main func(), options *newBenchmarkOptions) {
+	bm := benchmark{name: name, main: main}
+	if options != nil {
+		bm.init = options.init
+	}
+	allBenchmarks = append(allBenchmarks, bm)
+}
+
+var _ = Describe("Podman Benchmark Suite", func() {
+	var (
+		timedir    string
+		podmanTest *PodmanTestIntegration
+	)
+
+	setup := func() {
+		tempdir, err := CreateTempDirInTempDir()
+		if err != nil {
+			os.Exit(1)
+		}
+		podmanTest = PodmanTestCreate(tempdir)
+		podmanTest.Setup()
+
+		timedir, err = CreateTempDirInTempDir()
+		if err != nil {
+			os.Exit(1)
+		}
+	}
+
+	cleanup := func() {
+		podmanTest.Cleanup()
+		os.RemoveAll(timedir)
+	}
+
+	totalMemoryInKb := func() (total uint64) {
+		files, err := ioutil.ReadDir(timedir)
+		if err != nil {
+			Fail(fmt.Sprintf("Error reading timing dir: %v", err))
+		}
+
+		for _, f := range files {
+			if f.IsDir() {
+				continue
+			}
+			raw, err := ioutil.ReadFile(path.Join(timedir, f.Name()))
+			if err != nil {
+				Fail(fmt.Sprintf("Error reading timing file: %v", err))
+			}
+			rawS := strings.TrimSuffix(string(raw), "\n")
+			number, err := strconv.ParseUint(rawS, 10, 64)
+			if err != nil {
+				Fail(fmt.Sprintf("Error converting timing file to numeric value: %v", err))
+			}
+			total += number
+		}
+
+		return total
+	}
+
+	// Make sure to clean up after the benchmarks.
+	AfterEach(func() {
+		cleanup()
+	})
+
+	// All benchmarks are executed here to have *one* table listing all data.
+	Measure("Podman Benchmark Suite", func(b Benchmarker) {
+		for i := range allBenchmarks {
+			setup()
+			bm := allBenchmarks[i]
+			if bm.init != nil {
+				bm.init()
+			}
+
+			// Set the time dir only for the main() function.
+			os.Setenv(EnvTimeDir, timedir)
+			b.Time("[CPU] "+bm.name, bm.main)
+			os.Unsetenv(EnvTimeDir)
+
+			mem := totalMemoryInKb()
+			b.RecordValueWithPrecision("[MEM] "+bm.name, float64(mem), "KB", 1)
+			cleanup()
+		}
+	}, numBenchmarkSamples)
+
+	BeforeEach(func() {
+
+		// --------------------------------------------------------------------------
+		// IMAGE BENCHMARKS
+		// --------------------------------------------------------------------------
+
+		newBenchmark("podman images", func() {
+			session := podmanTest.Podman([]string{"images"})
+			session.WaitWithDefaultTimeout()
+			Expect(session).Should(Exit(0))
+		}, nil)
+
+		newBenchmark("podman pull", func() {
+			session := podmanTest.Podman([]string{"pull", "quay.io/libpod/cirros"})
+			session.WaitWithDefaultTimeout()
+			Expect(session).Should(Exit(0))
+		}, nil)
+
+		// --------------------------------------------------------------------------
+		// CONTAINER BENCHMARKS
+		// --------------------------------------------------------------------------
+
+		newBenchmark("podman create", func() {
+			session := podmanTest.Podman([]string{"run", ALPINE, "true"})
+			session.WaitWithDefaultTimeout()
+			Expect(session).Should(Exit(0))
+		}, nil)
+
+		newBenchmark("podman start", func() {
+			session := podmanTest.Podman([]string{"start", "foo"})
+			session.WaitWithDefaultTimeout()
+			Expect(session).Should(Exit(0))
+		}, &newBenchmarkOptions{
+			init: func() {
+				session := podmanTest.Podman([]string{"create", "--name=foo", ALPINE, "true"})
+				session.WaitWithDefaultTimeout()
+				Expect(session).Should(Exit(0))
+			},
+		})
+
+		newBenchmark("podman run", func() {
+			session := podmanTest.Podman([]string{"run", ALPINE, "true"})
+			session.WaitWithDefaultTimeout()
+			Expect(session).Should(Exit(0))
+		}, nil)
+	})
+})
diff --git a/test/utils/utils.go b/test/utils/utils.go
index 57f002130..da56a3a2e 100644
--- a/test/utils/utils.go
+++ b/test/utils/utils.go
@@ -27,6 +27,8 @@ const (
 	CNI NetworkBackend = iota
 	// Netavark network backend
 	Netavark NetworkBackend = iota
+	// Env variable for creating time files.
+	EnvTimeDir = "_PODMAN_TIME_DIR"
 )
 
 func (n NetworkBackend) ToString() string {
@@ -96,6 +98,17 @@ func (p *PodmanTest) PodmanAsUserBase(args []string, uid, gid uint32, cwd string
 	if p.RemoteTest {
 		podmanBinary = p.RemotePodmanBinary
 	}
+
+	if timeDir := os.Getenv(EnvTimeDir); timeDir != "" {
+		timeFile, err := ioutil.TempFile(timeDir, ".time")
+		if err != nil {
+			Fail(fmt.Sprintf("Error creating time file: %v", err))
+		}
+		timeArgs := []string{"-f", "%M", "-o", timeFile.Name()}
+		timeCmd := append([]string{"/usr/bin/time"}, timeArgs...)
+		wrapper = append(timeCmd, wrapper...)
+	}
+
 	runCmd := append(wrapper, podmanBinary)
 	if p.NetworkBackend == Netavark {
 		runCmd = append(runCmd, []string{"--network-backend", "netavark"}...)