process_cgroup_test.go

package main

import (
	"bytes"
	"fmt"
	"regexp"
	"strconv"
	"strings"
	"testing"

	"go.opentelemetry.io/ebpf-profiler/libpf"
	"go.opentelemetry.io/ebpf-profiler/libpf/pfunsafe"
)

// Old implementation (cgroup v2 only)
var cgroupv2ContainerIDPattern = regexp.MustCompile(`0:.*?:.*?([0-9a-fA-F]{64})(?:\.scope)?(?:/[a-z]+)?$`)

func parseContainerIDOld(cgroupData []byte) libpf.String {
	lines := bytes.Split(cgroupData, []byte("\n"))
	for _, line := range lines {
		if bytes.Equal(line, []byte("0::/")) {
			continue
		}
		pathParts := cgroupv2ContainerIDPattern.FindSubmatch(line)
		if pathParts != nil {
			return libpf.Intern(string(pathParts[1]))
		}
	}
	return libpf.NullString
}

// New implementation (cgroup v1 and v2)
const (
	containerSourceBench = "[0-9a-f]{64}"
	taskSourceBench      = "[0-9a-f]{32}-\\d+"
)

var expContainerIDBench = regexp.MustCompile(fmt.Sprintf(`(%s|%s)(?:\.scope)?(?:/[a-z]+)?$`, containerSourceBench, taskSourceBench))

func parseContainerIDNew(cgroupData []byte) libpf.String {
	lines := bytes.Split(cgroupData, []byte("\n"))
	for _, b := range lines {
		if bytes.Equal(b, []byte("0::/")) {
			continue
		}
		line := pfunsafe.ToString(b)
		parts := strings.SplitN(line, ":", 3)
		_, err := strconv.Atoi(parts[0])
		if len(parts) == 3 && err == nil {
			sub := parts[2]
			if partsIdx := expContainerIDBench.FindStringSubmatchIndex(sub); len(partsIdx) == 4 {
				return libpf.Intern(sub[partsIdx[2]:partsIdx[3]])
			}
		}
	}
	return libpf.NullString
}

// Test data representing various cgroup formats
var testCases = []struct {
	name string
	data []byte
}{
	{
		name: "cgroupv2_kubernetes_containerd",
		data: []byte("0::/kubepods.slice/kubepods-burstable.slice/kubepods-burstable-podf6f2d169_f2ae_4afa-95ed_06ff2ed6b288.slice/cri-containerd-b4d6d161c62525d726fa394b27df30e14f8ea5646313ada576b390de70cfc8cc.scope\n"),
	},
	{
		name: "cgroupv2_docker",
		data: []byte("0::/system.slice/docker-b1eba9dfaeba29d8b80532a574a03ea3cac29384327f339c26da13649e2120df.scope\n"),
	},
	{
		name: "cgroupv1_kubernetes_memory",
		data: []byte("11:memory:/kubepods/besteffort/poda9c80282-3f6b-4d5b-84d5-a137a6668011/ed89697807a981b82f6245ac3a13be232c1e13435d52bc3f53060d61babe1997\n"),
	},
	{
		name: "cgroupv1_kubernetes_cpu",
		data: []byte("11:cpucpuacct:/system.slice/containerd.service/kubepods-besteffort-pod86811ae3_b633_4eb8_a508_e3eae190f6ce.slice:cri-containerd:da1bdd84c8b25938081afe48da7075e2a211d2b1a62e01c894b4e5f3ffab670a\n"),
	},
	{
		name: "cgroupv1_systemd",
		data: []byte("1:name=systemd:/kubepods.slice/kubepods-burstable.slice/kubepods-burstable-podf6f2d169_f2ae_4afa_95ed_06ff2ed6b288.slice/cri-containerd-b4d6d161c62525d726fa394b27df30e14f8ea5646313ada576b390de70cfc8cc.scope\n"),
	},
	{
		name: "cgroupv2_multiple_lines",
		data: []byte(`0::/
0::/system.slice/docker-a1b2c3d4e5f6a7b8c9d0e1f2a3b4c5d6e7f8a9b0c1d2e3f4a5b6c7d8e9f0a1b2.scope
`),
	},
	{
		name: "cgroupv1_multiple_hierarchies",
		data: []byte(`12:perf_event:/kubepods/besteffort/pod123/container456
11:memory:/kubepods/besteffort/poda9c80282-3f6b-4d5b-84d5-a137a6668011/ed89697807a981b82f6245ac3a13be232c1e13435d52bc3f53060d61babe1997
10:devices:/kubepods/besteffort/pod123/container456
`),
	},
	{
		name: "no_container",
		data: []byte("0::/user.slice/user-1000.slice/user@1000.service\n"),
	},
}

// Benchmark old implementation (cgroup v2 only)
func BenchmarkParseContainerID_Old(b *testing.B) {
	for _, tc := range testCases {
		b.Run(tc.name, func(b *testing.B) {
			b.ReportAllocs()
			b.ResetTimer()
			for i := 0; i < b.N; i++ {
				_ = parseContainerIDOld(tc.data)
			}
		})
	}
}

// Benchmark new implementation (cgroup v1 and v2)
func BenchmarkParseContainerID_New(b *testing.B) {
	for _, tc := range testCases {
		b.Run(tc.name, func(b *testing.B) {
			b.ReportAllocs()
			b.ResetTimer()
			for i := 0; i < b.N; i++ {
				_ = parseContainerIDNew(tc.data)
			}
		})
	}
}

// Comparison benchmark - measures percentage difference
func BenchmarkParseContainerID_Comparison(b *testing.B) {
	b.Run("Old_vs_New_AllCases", func(b *testing.B) {
		b.Run("Old", func(b *testing.B) {
			b.ReportAllocs()
			for i := 0; i < b.N; i++ {
				for _, tc := range testCases {
					_ = parseContainerIDOld(tc.data)
				}
			}
		})
		b.Run("New", func(b *testing.B) {
			b.ReportAllocs()
			for i := 0; i < b.N; i++ {
				for _, tc := range testCases {
					_ = parseContainerIDNew(tc.data)
				}
			}
		})
	})
}

// Benchmark with realistic multi-line cgroup files
func BenchmarkParseContainerID_Realistic(b *testing.B) {
	// Realistic cgroup v1 file with multiple controller hierarchies
	cgroupv1Data := []byte(`12:perf_event:/kubepods/besteffort/pod86811ae3-b633-4eb8-a508-e3eae190f6ce/da1bdd84c8b25938081afe48da7075e2a211d2b1a62e01c894b4e5f3ffab670a
11:memory:/kubepods/besteffort/pod86811ae3-b633-4eb8-a508-e3eae190f6ce/da1bdd84c8b25938081afe48da7075e2a211d2b1a62e01c894b4e5f3ffab670a
10:devices:/kubepods/besteffort/pod86811ae3-b633-4eb8-a508-e3eae190f6ce/da1bdd84c8b25938081afe48da7075e2a211d2b1a62e01c894b4e5f3ffab670a
9:hugetlb:/kubepods/besteffort/pod86811ae3-b633-4eb8-a508-e3eae190f6ce/da1bdd84c8b25938081afe48da7075e2a211d2b1a62e01c894b4e5f3ffab670a
8:blkio:/kubepods/besteffort/pod86811ae3-b633-4eb8-a508-e3eae190f6ce/da1bdd84c8b25938081afe48da7075e2a211d2b1a62e01c894b4e5f3ffab670a
7:freezer:/kubepods/besteffort/pod86811ae3-b633-4eb8-a508-e3eae190f6ce/da1bdd84c8b25938081afe48da7075e2a211d2b1a62e01c894b4e5f3ffab670a
6:cpuset:/kubepods/besteffort/pod86811ae3-b633-4eb8-a508-e3eae190f6ce/da1bdd84c8b25938081afe48da7075e2a211d2b1a62e01c894b4e5f3ffab670a
5:net_cls,net_prio:/kubepods/besteffort/pod86811ae3-b633-4eb8-a508-e3eae190f6ce/da1bdd84c8b25938081afe48da7075e2a211d2b1a62e01c894b4e5f3ffab670a
4:pids:/kubepods/besteffort/pod86811ae3-b633-4eb8-a508-e3eae190f6ce/da1bdd84c8b25938081afe48da7075e2a211d2b1a62e01c894b4e5f3ffab670a
3:cpu,cpuacct:/kubepods/besteffort/pod86811ae3-b633-4eb8-a508-e3eae190f6ce/da1bdd84c8b25938081afe48da7075e2a211d2b1a62e01c894b4e5f3ffab670a
2:rdma:/
1:name=systemd:/kubepods/besteffort/pod86811ae3-b633-4eb8-a508-e3eae190f6ce/da1bdd84c8b25938081afe48da7075e2a211d2b1a62e01c894b4e5f3ffab670a
`)

	// Realistic cgroup v2 file (unified hierarchy)
	cgroupv2Data := []byte(`0::/system.slice/docker-b4d6d161c62525d726fa394b27df30e14f8ea5646313ada576b390de70cfc8cc.scope
`)

	b.Run("Realistic_cgroupv1", func(b *testing.B) {
		b.Run("Old", func(b *testing.B) {
			b.ReportAllocs()
			b.ResetTimer()
			for i := 0; i < b.N; i++ {
				_ = parseContainerIDOld(cgroupv1Data)
			}
		})
		b.Run("New", func(b *testing.B) {
			b.ReportAllocs()
			b.ResetTimer()
			for i := 0; i < b.N; i++ {
				_ = parseContainerIDNew(cgroupv1Data)
			}
		})
	})

	b.Run("Realistic_cgroupv2", func(b *testing.B) {
		b.Run("Old", func(b *testing.B) {
			b.ReportAllocs()
			b.ResetTimer()
			for i := 0; i < b.N; i++ {
				_ = parseContainerIDOld(cgroupv2Data)
			}
		})
		b.Run("New", func(b *testing.B) {
			b.ReportAllocs()
			b.ResetTimer()
			for i := 0; i < b.N; i++ {
				_ = parseContainerIDNew(cgroupv2Data)
			}
		})
	})
}

// Benchmark regex compilation impact (one-time cost)
func BenchmarkRegexCompilation(b *testing.B) {
	b.Run("Old_Pattern", func(b *testing.B) {
		for i := 0; i < b.N; i++ {
			_ = regexp.MustCompile(`0:.*?:.*?([0-9a-fA-F]{64})(?:\.scope)?(?:/[a-z]+)?$`)
		}
	})
	b.Run("New_Pattern", func(b *testing.B) {
		for i := 0; i < b.N; i++ {
			_ = regexp.MustCompile(fmt.Sprintf(`(%s|%s)(?:\.scope)?(?:/[a-z]+)?$`, containerSourceBench, taskSourceBench))
		}
	})
}

results.txt

$ go test -bench=.
goos: linux
goarch: amd64
pkg: 1173
cpu: 12th Gen Intel(R) Core(TM) i7-12700H
BenchmarkParseContainerID_Old/cgroupv2_kubernetes_containerd-20         	  328604	      3596 ns/op	     161 B/op	       3 allocs/op
BenchmarkParseContainerID_Old/cgroupv2_docker-20                        	 1266465	       954.4 ns/op	     160 B/op	       3 allocs/op
BenchmarkParseContainerID_Old/cgroupv1_kubernetes_memory-20             	12299006	        93.41 ns/op	      48 B/op	       1 allocs/op
BenchmarkParseContainerID_Old/cgroupv1_kubernetes_cpu-20                	11435577	       105.6 ns/op	      48 B/op	       1 allocs/op
BenchmarkParseContainerID_Old/cgroupv1_systemd-20                       	11551842	       103.0 ns/op	      48 B/op	       1 allocs/op
BenchmarkParseContainerID_Old/cgroupv2_multiple_lines-20                	 1239174	       954.7 ns/op	     192 B/op	       3 allocs/op
BenchmarkParseContainerID_Old/cgroupv1_multiple_hierarchies-20          	 9836048	       113.5 ns/op	      96 B/op	       1 allocs/op
BenchmarkParseContainerID_Old/no_container-20                           	32114302	        36.27 ns/op	      48 B/op	       1 allocs/op
BenchmarkParseContainerID_New/cgroupv2_kubernetes_containerd-20         	  195297	      5624 ns/op	     128 B/op	       3 allocs/op
BenchmarkParseContainerID_New/cgroupv2_docker-20                        	 1000000	      1131 ns/op	     128 B/op	       3 allocs/op
BenchmarkParseContainerID_New/cgroupv1_kubernetes_memory-20             	  326467	      3462 ns/op	     128 B/op	       3 allocs/op
BenchmarkParseContainerID_New/cgroupv1_kubernetes_cpu-20                	  202774	      5433 ns/op	     128 B/op	       3 allocs/op
BenchmarkParseContainerID_New/cgroupv1_systemd-20                       	  193164	      5537 ns/op	     128 B/op	       3 allocs/op
BenchmarkParseContainerID_New/cgroupv2_multiple_lines-20                	  998610	      1167 ns/op	     160 B/op	       3 allocs/op
BenchmarkParseContainerID_New/cgroupv1_multiple_hierarchies-20          	  227343	      5062 ns/op	     225 B/op	       4 allocs/op
BenchmarkParseContainerID_New/no_container-20                           	  713857	      1632 ns/op	     160 B/op	       4 allocs/op
BenchmarkParseContainerID_Comparison/Old_vs_New_AllCases/Old-20         	  179330	      6101 ns/op	     803 B/op	      14 allocs/op
BenchmarkParseContainerID_Comparison/Old_vs_New_AllCases/New-20         	   41179	     29348 ns/op	    1190 B/op	      26 allocs/op
BenchmarkParseContainerID_Realistic/Realistic_cgroupv1/Old-20           	  446925	      2731 ns/op	     433 B/op	       3 allocs/op
BenchmarkParseContainerID_Realistic/Realistic_cgroupv1/New-20           	  327992	      3714 ns/op	     401 B/op	       3 allocs/op
BenchmarkParseContainerID_Realistic/Realistic_cgroupv2/Old-20           	 1282798	       923.7 ns/op	     160 B/op	       3 allocs/op
BenchmarkParseContainerID_Realistic/Realistic_cgroupv2/New-20           	  918933	      1135 ns/op	     128 B/op	       3 allocs/op
BenchmarkRegexCompilation/Old_Pattern-20                                	  163942	      7281 ns/op
BenchmarkRegexCompilation/New_Pattern-20                                	  174321	      8145 ns/op
PASS
ok  	1173	33.048s