Files
seaweedfs/weed/mount/weedfs_dir_read_bench_test.go
T
Chris Lu bd3b75b534 mount: let a readdirplus stop taking references at a cap
The inode table only shrinks when the kernel returns a reference, so a walk
over a large tree grows it with every child it touches and nothing gives any
of it back until the kernel reclaims dentries. On a mount with tens of
millions of files that is most of the process's heap.

-maxInodeEntries stops the speculative half of that. Past the cap a
readdirplus still reports every name, but leaves the EntryOut zeroed: Linux
reads a zero nodeid as 'no attributes for this entry', takes no reference, and
looks up the ones the client actually needs. A LOOKUP is never refused, so the
table can still grow past the cap by what a client really asks for, and
nothing here evicts. Default 0 keeps today's behavior.
2026-08-18 21:00:49 -07:00

228 lines
6.6 KiB
Go

package mount
import (
"context"
"fmt"
"os"
"path/filepath"
"testing"
"time"
"github.com/seaweedfs/go-fuse/v2/fuse"
"github.com/seaweedfs/seaweedfs/weed/filer"
"github.com/seaweedfs/seaweedfs/weed/mount/meta_cache"
"github.com/seaweedfs/seaweedfs/weed/pb"
"github.com/seaweedfs/seaweedfs/weed/pb/filer_pb"
"github.com/seaweedfs/seaweedfs/weed/util"
"google.golang.org/grpc"
"google.golang.org/grpc/credentials/insecure"
)
const benchDirEntryCount = 200000
// benchSink drains a readdir the way a front end does. sinkLimit is how many
// entries one round accepts, standing in for the kernel reply buffer or the
// WinFsp adapter's batch.
type benchSink struct {
plus bool
takesRef bool
sinkLimit int
count int
inodes []uint64
lastOff uint64
attrs []fuse.EntryOut
}
func (s *benchSink) reset() {
s.count = 0
s.inodes = s.inodes[:0]
s.attrs = s.attrs[:0]
}
func (s *benchSink) AddEntry(entry fuse.DirEntry) bool {
if s.count >= s.sinkLimit {
return false
}
s.count++
s.lastOff = entry.Off
s.inodes = append(s.inodes, entry.Ino)
return true
}
func (s *benchSink) AddEntryPlus(entry fuse.DirEntry) *fuse.EntryOut {
if s.count >= s.sinkLimit {
return nil
}
s.count++
s.lastOff = entry.Off
s.inodes = append(s.inodes, entry.Ino)
s.attrs = append(s.attrs, fuse.EntryOut{})
return &s.attrs[len(s.attrs)-1]
}
func (s *benchSink) TakesLookupRef() bool { return s.takesRef }
func newBenchWFS(tb testing.TB, dir util.FullPath, n int) *WFS {
tb.Helper()
uidGidMapper, err := meta_cache.NewUidGidMapper("", "")
if err != nil {
tb.Fatalf("uid/gid mapper: %v", err)
}
root := util.FullPath("/")
option := &Option{
ChunkSizeLimit: 1024,
ConcurrentReaders: 1,
VolumeServerAccess: "filerProxy",
FilerAddresses: []pb.ServerAddress{pb.NewServerAddressWithGrpcPort("127.0.0.1:1", 1)},
GrpcDialOption: grpc.WithTransportCredentials(insecure.NewCredentials()),
FilerMountRootPath: "/",
MountUid: 99,
MountGid: 100,
MountMode: 0o777,
MountMtime: time.Now(),
MountCtime: time.Now(),
UidGidMapper: uidGidMapper,
}
wfs := &WFS{
option: option,
signature: 1,
inodeToPath: NewInodeToPath(root, 0),
fhMap: NewFileHandleToInode(),
dhMap: NewDirectoryHandleToInode(),
fhLockTable: util.NewLockTable[FileHandleId](),
hardLinkLockTable: util.NewLockTable[string](),
}
wfs.metaCache = meta_cache.NewMetaCache(
filepath.Join(tb.TempDir(), "meta"),
uidGidMapper,
root,
false,
func(path util.FullPath) { wfs.inodeToPath.MarkChildrenCached(path) },
func(path util.FullPath) bool { return wfs.inodeToPath.IsChildrenCached(path) },
func(meta_cache.EntryInvalidation) {},
nil,
)
tb.Cleanup(wfs.metaCache.Shutdown)
now := time.Now()
ctx := context.Background()
if err := wfs.metaCache.InsertEntry(ctx, &filer.Entry{
FullPath: dir,
Attr: filer.Attr{Mode: os.ModeDir | 0o755, Mtime: now, Crtime: now, Uid: 99, Gid: 100},
}, 0); err != nil {
tb.Fatalf("insert dir: %v", err)
}
for i := 0; i < n; i++ {
child := dir.Child(fmt.Sprintf("image-%08d.jpg", i))
if err := wfs.metaCache.InsertEntry(ctx, &filer.Entry{
FullPath: child,
// The filer stamps an inode on every entry it stores, so a listing
// arrives with one and never has to derive its own.
Attr: filer.Attr{Mode: 0o644, Mtime: now, Crtime: now, Uid: 99, Gid: 100, FileSize: 4 << 20, Inode: child.AsInode(now.Unix())},
// A real file has chunks, and building them is most of what decoding
// an entry costs.
// No FileId: BeforeEntrySerialization reparses that legacy string
// over Fid on the way in, which would make every entry's chunk
// byte-identical instead of varying per file.
Chunks: []*filer_pb.FileChunk{{
Size: 4 << 20, ModifiedTsNs: now.UnixNano(),
ETag: "1a2b3c4d5e6f7890",
Fid: &filer_pb.FileId{VolumeId: 3, FileKey: uint64(i), Cookie: 0x1637037d},
}},
}, 0); err != nil {
tb.Fatalf("insert entry %d: %v", i, err)
}
}
// Mark the tree cached so the listing is served from the meta cache and no
// filer client is dialled.
wfs.inodeToPath.MarkChildrenCached(root)
wfs.inodeToPath.Lookup(dir, now.Unix(), true, false, 0, true)
wfs.inodeToPath.MarkChildrenCached(dir)
return wfs
}
// walkOnce enumerates the whole directory the way a front end does: repeated
// rounds against one handle until the listing runs dry, returning whatever
// references the round took.
func walkOnce(tb testing.TB, wfs *WFS, dirInode uint64, sink *benchSink, forgets bool) int {
dhid, _ := wfs.AcquireDirectoryHandle()
defer wfs.ReleaseDirectoryHandle(dhid)
total := 0
offset := uint64(0)
for {
sink.reset()
status := wfs.doReadDirectory(&fuse.ReadIn{
InHeader: fuse.InHeader{NodeId: dirInode},
Fh: uint64(dhid),
Offset: offset,
Size: 1 << 20,
}, sink, sink.plus)
if status != fuse.OK {
tb.Fatalf("readdir: %v", status)
}
if sink.count == 0 {
return total
}
total += sink.count
if forgets {
// HasInode keeps this to the entries that really hold a reference,
// so a listing that took none is not charged for a bogus Forget.
for _, ino := range sink.inodes {
if wfs.inodeToPath.HasInode(ino) {
wfs.Forget(ino, 1)
}
}
}
if sink.lastOff <= offset {
return total
}
offset = sink.lastOff
}
}
var benchCases = []struct {
name string
plus bool
// ref mirrors the sink's TakesLookupRef. The kernel's reports true whatever
// the mode, exactly as fuseDirEntryList does; it is the mode that decides
// whether a reference is actually granted.
ref bool
// forgets is what the front end does after a round: the kernel returns one
// FORGET per readdirplus entry and none for a plain readdir, and the WinFsp
// adapter hands back everything a round gave it.
forgets bool
}{
{"kernel_readdir", false, true, false},
{"kernel_readdirplus", true, true, true},
{"winfsp_readdirplus", true, false, true},
}
func BenchmarkReadDirectory(b *testing.B) {
dir := util.FullPath("/images")
for _, tc := range benchCases {
b.Run(tc.name, func(b *testing.B) {
wfs := newBenchWFS(b, dir, benchDirEntryCount)
dirInode, _ := wfs.inodeToPath.GetInode(dir)
sink := &benchSink{plus: tc.plus, takesRef: tc.ref, sinkLimit: 4096}
b.ResetTimer()
b.ReportAllocs()
for i := 0; i < b.N; i++ {
if got := walkOnce(b, wfs, dirInode, sink, tc.forgets); got != benchDirEntryCount+2 {
b.Fatalf("listed %d entries, want %d", got, benchDirEntryCount+2)
}
}
b.StopTimer()
// What the listing left in the inode table, over the root and the
// directory itself.
b.ReportMetric(float64(wfs.inodeToPath.Len()), "inodes_left")
})
}
}