common/system/exec2/exec2_windows_test.go

// Copyright 2019 The LUCI Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package exec2

import (
	"os/exec"
	"strconv"
	"syscall"
	"testing"

	"golang.org/x/sys/windows"
)

func BenchmarkIterateChildThreads(b *testing.B) {
	nop := func(uint32) error {
		return nil
	}

	createProcess := func() *exec.Cmd {
		cmd := exec.Command("go.exe")
		cmd.SysProcAttr = &syscall.SysProcAttr{
			CreationFlags: windows.CREATE_SUSPENDED,
		}

		if err := cmd.Start(); err != nil {
			b.Fatal(err)
		}
		return cmd
	}

	b.Run("parallel", func(b *testing.B) {
		cmd := createProcess()

		b.ResetTimer()
		b.RunParallel(func(pb *testing.PB) {
			for pb.Next() {
				if err := iterateChildThreads(uint32(cmd.Process.Pid), nop); err != nil {
					b.Fatal(err)
				}
			}
		})
		b.StopTimer()
		if err := cmd.Process.Kill(); err != nil {
			b.Fatal(err)
		}
	})

	for _, numProcess := range []int{1, 10, 100, 1000} {
		b.Run("many process "+strconv.Itoa(numProcess), func(b *testing.B) {
			cmds := make([]*exec.Cmd, numProcess)
			for i := range cmds {
				cmds[i] = createProcess()
			}

			b.ResetTimer()
			for i := 0; i < b.N; i++ {
				pid := uint32(cmds[i%len(cmds)].Process.Pid)
				if err := iterateChildThreads(pid, nop); err != nil {
					b.Fatal(err)
				}
			}
			b.StopTimer()

			for _, cmd := range cmds {
				if err := cmd.Process.Kill(); err != nil {
					b.Fatal(err)
				}
			}
		})
	}
}