mount: improve read performance on random reads

This commit is contained in:
chrislu 2021-12-19 22:43:14 -08:00
parent 85c526c583
commit a152f17937
5 changed files with 66 additions and 7 deletions

View file

@ -101,6 +101,15 @@ func fetchChunk(lookupFileIdFn wdclient.LookupFileIdFunctionType, fileId string,
return retriedFetchChunkData(urlStrings, cipherKey, isGzipped, true, 0, 0)
}
func fetchChunkRange(lookupFileIdFn wdclient.LookupFileIdFunctionType, fileId string, cipherKey []byte, isGzipped bool, offset int64, size int) ([]byte, error) {
urlStrings, err := lookupFileIdFn(fileId)
if err != nil {
glog.Errorf("operation LookupFileId %s failed, err: %v", fileId, err)
return nil, err
}
return retriedFetchChunkData(urlStrings, cipherKey, isGzipped, false, offset, size)
}
func retriedFetchChunkData(urlStrings []string, cipherKey []byte, isGzipped bool, isFullChunk bool, offset int64, size int) ([]byte, error) {
var err error

View file

@ -26,6 +26,7 @@ type ChunkReadAt struct {
chunkCache chunk_cache.ChunkCache
lastChunkFileId string
lastChunkData []byte
readerPattern *ReaderPattern
}
var _ = io.ReaderAt(&ChunkReadAt{})
@ -92,6 +93,7 @@ func NewChunkReaderAtFromClient(lookupFn wdclient.LookupFileIdFunctionType, chun
lookupFileId: lookupFn,
chunkCache: chunkCache,
fileSize: fileSize,
readerPattern: NewReaderPattern(),
}
}
@ -106,6 +108,8 @@ func (c *ChunkReadAt) ReadAt(p []byte, offset int64) (n int, err error) {
c.readerLock.Lock()
defer c.readerLock.Unlock()
c.readerPattern.MonitorReadAt(offset, len(p))
// glog.V(4).Infof("ReadAt [%d,%d) of total file size %d bytes %d chunk views", offset, offset+int64(len(p)), c.fileSize, len(c.chunkViews))
return c.doReadAt(p, offset)
}
@ -171,6 +175,10 @@ func (c *ChunkReadAt) doReadAt(p []byte, offset int64) (n int, err error) {
func (c *ChunkReadAt) readChunkSlice(chunkView *ChunkView, nextChunkViews *ChunkView, offset, length uint64) ([]byte, error) {
if c.readerPattern.IsRandomMode() {
return c.doFetchRangeChunkData(chunkView, offset, length)
}
chunkSlice := c.chunkCache.GetChunkSlice(chunkView.FileId, offset, length)
if len(chunkSlice) > 0 {
return chunkSlice, nil
@ -243,3 +251,15 @@ func (c *ChunkReadAt) doFetchFullChunkData(chunkView *ChunkView) ([]byte, error)
return data, err
}
func (c *ChunkReadAt) doFetchRangeChunkData(chunkView *ChunkView, offset, length uint64) ([]byte, error) {
glog.V(4).Infof("+ doFetchFullChunkData %s", chunkView.FileId)
data, err := fetchChunkRange(c.lookupFileId, chunkView.FileId, chunkView.CipherKey, chunkView.IsGzipped, int64(offset), int(length))
glog.V(4).Infof("- doFetchFullChunkData %s", chunkView.FileId)
return data, err
}

View file

@ -0,0 +1,31 @@
package filer
type ReaderPattern struct {
isStreaming bool
lastReadOffset int64
}
// For streaming read: only cache the first chunk
// For random read: only fetch the requested range, instead of the whole chunk
func NewReaderPattern() *ReaderPattern {
return &ReaderPattern{
isStreaming: true,
lastReadOffset: 0,
}
}
func (rp *ReaderPattern) MonitorReadAt(offset int64, size int) {
if rp.lastReadOffset > offset {
rp.isStreaming = false
}
rp.lastReadOffset = offset
}
func (rp *ReaderPattern) IsStreamingMode() bool {
return rp.isStreaming
}
func (rp *ReaderPattern) IsRandomMode() bool {
return !rp.isStreaming
}

View file

@ -62,10 +62,11 @@ var _ = fs.HandleReleaser(&FileHandle{})
func (fh *FileHandle) Read(ctx context.Context, req *fuse.ReadRequest, resp *fuse.ReadResponse) error {
glog.V(4).Infof("%s read fh %d: [%d,%d) size %d resp.Data cap=%d", fh.f.fullpath(), fh.handle, req.Offset, req.Offset+int64(req.Size), req.Size, cap(resp.Data))
fh.Lock()
defer fh.Unlock()
glog.V(4).Infof("%s read fh %d: [%d,%d) size %d resp.Data cap=%d", fh.f.fullpath(), fh.handle, req.Offset, req.Offset+int64(req.Size), req.Size, cap(resp.Data))
if req.Size <= 0 {
return nil
}

View file

@ -29,8 +29,6 @@ var fileNameEscaper = strings.NewReplacer(`\`, `\\`, `"`, `\"`)
func (vs *VolumeServer) GetOrHeadHandler(w http.ResponseWriter, r *http.Request) {
glog.V(9).Info(r.Method + " " + r.URL.Path + " " + r.Header.Get("Range"))
stats.VolumeServerRequestCounter.WithLabelValues("get").Inc()
start := time.Now()
defer func() { stats.VolumeServerRequestHistogram.WithLabelValues("get").Observe(time.Since(start).Seconds()) }()