@UnstableApi public final class WeightedFairQueueByteDistributor extends Object implements StreamByteDistributor
StreamByteDistributorthat is sensitive to stream priority and uses Weighted Fair Queueing approach for distributing bytes.
Inspiration for this distributor was taken from Linux's Completely Fair Scheduler to model the distribution of bytes to simulate an "ideal multi-tasking CPU", but in this case we are simulating an "ideal multi-tasking NIC".
Each write operation will use the
allocationQuantum(int) to know how many more bytes should be allocated
relative to the next stream which wants to write. This is to balance fairness while also considering goodput.
|Constructor and Description|
|Modifier and Type||Method and Description|
Sets the amount of bytes that will be allocated to each stream.
Distributes up to
Explicitly update the dependency tree.
Called when the streamable bytes for a stream has changed.
public WeightedFairQueueByteDistributor(Http2Connection connection)
public WeightedFairQueueByteDistributor(Http2Connection connection, int maxStateOnlySize)
public void updateStreamableBytes(StreamByteDistributor.StreamState state)
public void updateDependencyTree(int childStreamId, int parentStreamId, short weight, boolean exclusive)
childStreamId- The stream identifier associated with the child stream.
parentStreamId- The stream identifier associated with the parent stream. May be
0, to make
childStreamIdand immediate child of the connection.
weight- The weight which is used relative to other child streams for
parentStreamId. This value must be between 1 and 256 (inclusive).
childStreamIdshould be the exclusive dependency of
public boolean distribute(int maxBytes, StreamByteDistributor.Writer writer) throws Http2Exception
maxBytesto those streams containing streamable bytes and iterates across those streams to write the appropriate bytes. Criteria for traversing streams is undefined and it is up to the implementation to determine when to stop at a given stream.
The streamable bytes are not automatically updated by calling this method. It is up to the
caller to indicate the number of bytes streamable after the write by calling
maxBytes- the maximum number of bytes to write.
trueif there are still streamable bytes that have not yet been written, otherwise
Http2Exception- If an internal exception occurs and internal connection state would otherwise be corrupted.
public void allocationQuantum(int allocationQuantum)
allocationQuantum- the amount of bytes that will be allocated to each stream. Must be > 0.
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