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// Copyright 2019 The gVisor 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.
// These benchmarks emulate memfs benchmarks. Ext4 images must be created
// before this benchmark is run using the `make_deep_ext4.sh` script at
// /tmp/image-{depth}.ext4 for all the depths tested below.
//
// The benchmark itself cannot run the script because the script requires
// sudo privileges to create the file system images.
package benchmark_test
import (
"fmt"
"os"
"runtime"
"strings"
"testing"
"gvisor.dev/gvisor/pkg/context"
"gvisor.dev/gvisor/pkg/fspath"
"gvisor.dev/gvisor/pkg/sentry/contexttest"
"gvisor.dev/gvisor/pkg/sentry/fsimpl/ext"
"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
"gvisor.dev/gvisor/pkg/sentry/vfs"
)
var depths = []int{1, 2, 3, 8, 64, 100}
const filename = "file.txt"
// setUp opens imagePath as an ext Filesystem and returns all necessary
// elements required to run tests. If error is nil, it also returns a tear
// down function which must be called after the test is run for clean up.
func setUp(b *testing.B, imagePath string) (context.Context, *vfs.VirtualFilesystem, *vfs.VirtualDentry, func(), error) {
f, err := os.Open(imagePath)
if err != nil {
return nil, nil, nil, nil, err
}
ctx := contexttest.Context(b)
creds := auth.CredentialsFromContext(ctx)
// Create VFS.
vfsObj := vfs.New()
vfsObj.MustRegisterFilesystemType("extfs", ext.FilesystemType{}, &vfs.RegisterFilesystemTypeOptions{
AllowUserMount: true,
})
mntns, err := vfsObj.NewMountNamespace(ctx, creds, imagePath, "extfs", &vfs.GetFilesystemOptions{InternalData: int(f.Fd())})
if err != nil {
f.Close()
return nil, nil, nil, nil, err
}
root := mntns.Root()
tearDown := func() {
root.DecRef()
if err := f.Close(); err != nil {
b.Fatalf("tearDown failed: %v", err)
}
}
return ctx, vfsObj, &root, tearDown, nil
}
// mount mounts extfs at the path operation passed. Returns a tear down
// function which must be called after the test is run for clean up.
func mount(b *testing.B, imagePath string, vfsfs *vfs.VirtualFilesystem, pop *vfs.PathOperation) func() {
b.Helper()
f, err := os.Open(imagePath)
if err != nil {
b.Fatalf("could not open image at %s: %v", imagePath, err)
}
ctx := contexttest.Context(b)
creds := auth.CredentialsFromContext(ctx)
if err := vfsfs.MountAt(ctx, creds, imagePath, pop, "extfs", &vfs.MountOptions{
GetFilesystemOptions: vfs.GetFilesystemOptions{
InternalData: int(f.Fd()),
},
}); err != nil {
b.Fatalf("failed to mount tmpfs submount: %v", err)
}
return func() {
if err := f.Close(); err != nil {
b.Fatalf("tearDown failed: %v", err)
}
}
}
// BenchmarkVFS2Ext4fsStat emulates BenchmarkVFS2MemfsStat.
func BenchmarkVFS2Ext4fsStat(b *testing.B) {
for _, depth := range depths {
b.Run(fmt.Sprintf("%d", depth), func(b *testing.B) {
ctx, vfsfs, root, tearDown, err := setUp(b, fmt.Sprintf("/tmp/image-%d.ext4", depth))
if err != nil {
b.Fatalf("setUp failed: %v", err)
}
defer tearDown()
creds := auth.CredentialsFromContext(ctx)
var filePathBuilder strings.Builder
filePathBuilder.WriteByte('/')
for i := 1; i <= depth; i++ {
filePathBuilder.WriteString(fmt.Sprintf("%d", i))
filePathBuilder.WriteByte('/')
}
filePathBuilder.WriteString(filename)
filePath := filePathBuilder.String()
runtime.GC()
b.ResetTimer()
for i := 0; i < b.N; i++ {
stat, err := vfsfs.StatAt(ctx, creds, &vfs.PathOperation{
Root: *root,
Start: *root,
Path: fspath.Parse(filePath),
FollowFinalSymlink: true,
}, &vfs.StatOptions{})
if err != nil {
b.Fatalf("stat(%q) failed: %v", filePath, err)
}
// Sanity check.
if stat.Size > 0 {
b.Fatalf("got wrong file size (%d)", stat.Size)
}
}
})
}
}
// BenchmarkVFS2ExtfsMountStat emulates BenchmarkVFS2MemfsMountStat.
func BenchmarkVFS2ExtfsMountStat(b *testing.B) {
for _, depth := range depths {
b.Run(fmt.Sprintf("%d", depth), func(b *testing.B) {
// Create root extfs with depth 1 so we can mount extfs again at /1/.
ctx, vfsfs, root, tearDown, err := setUp(b, fmt.Sprintf("/tmp/image-%d.ext4", 1))
if err != nil {
b.Fatalf("setUp failed: %v", err)
}
defer tearDown()
creds := auth.CredentialsFromContext(ctx)
mountPointName := "/1/"
pop := vfs.PathOperation{
Root: *root,
Start: *root,
Path: fspath.Parse(mountPointName),
}
// Save the mount point for later use.
mountPoint, err := vfsfs.GetDentryAt(ctx, creds, &pop, &vfs.GetDentryOptions{})
if err != nil {
b.Fatalf("failed to walk to mount point: %v", err)
}
defer mountPoint.DecRef()
// Create extfs submount.
mountTearDown := mount(b, fmt.Sprintf("/tmp/image-%d.ext4", depth), vfsfs, &pop)
defer mountTearDown()
var filePathBuilder strings.Builder
filePathBuilder.WriteString(mountPointName)
for i := 1; i <= depth; i++ {
filePathBuilder.WriteString(fmt.Sprintf("%d", i))
filePathBuilder.WriteByte('/')
}
filePathBuilder.WriteString(filename)
filePath := filePathBuilder.String()
runtime.GC()
b.ResetTimer()
for i := 0; i < b.N; i++ {
stat, err := vfsfs.StatAt(ctx, creds, &vfs.PathOperation{
Root: *root,
Start: *root,
Path: fspath.Parse(filePath),
FollowFinalSymlink: true,
}, &vfs.StatOptions{})
if err != nil {
b.Fatalf("stat(%q) failed: %v", filePath, err)
}
// Sanity check. touch(1) always creates files of size 0 (empty).
if stat.Size > 0 {
b.Fatalf("got wrong file size (%d)", stat.Size)
}
}
})
}
}
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