always prefetch at least 5 blocks ahead
This should reduce stuttering when streaming. License: MIT Signed-off-by: Steven Allen <steven@stebalien.com>
Steven Allen committed
Jun 27, 2018 at 17:08 UTC
ff3efb5646437ac77c6b75e0452b239d154928c5
1 file changed
+8
-4
unixfs/io/pbdagreader.go
+8
-4
@@ -68,8 +68,7 @@ func NewPBFileReader(ctx context.Context, n *mdag.ProtoNode, pb *ftpb.Data, serv
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const preloadSize = 10
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-func (dr *PBDagReader) preloadNextNodes(ctx context.Context) {
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- beg := dr.linkPosition
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+func (dr *PBDagReader) preload(ctx context.Context, beg int) {
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end := beg + preloadSize
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if end >= len(dr.links) {
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end = len(dr.links)
@@ -90,8 +89,13 @@ func (dr *PBDagReader) precalcNextBuf(ctx context.Context) error {
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return io.EOF
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}
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- if dr.promises[dr.linkPosition] == nil {
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- dr.preloadNextNodes(ctx)
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+ // If we drop to <= preloadSize/2 preloading nodes, preload the next 10.
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+ for i := dr.linkPosition; i < dr.linkPosition+preloadSize/2 && i < len(dr.promises); i++ {
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+ // TODO: check if canceled.
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+ if dr.promises[i] == nil {
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+ dr.preload(ctx, i)
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+ break
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+ }
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}
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nxt, err := dr.promises[dr.linkPosition].Get(ctx)