io.aeron.driver.PreferredMulticastFlowControl Maven / Gradle / Ivy
/*
* Copyright 2014-2019 Real Logic Ltd.
*
* 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.
*/
package io.aeron.driver;
import io.aeron.protocol.StatusMessageFlyweight;
import org.agrona.BitUtil;
import org.agrona.collections.ArrayListUtil;
import java.net.InetSocketAddress;
import java.util.ArrayList;
import java.util.concurrent.TimeUnit;
import static io.aeron.logbuffer.LogBufferDescriptor.computePosition;
import static java.lang.System.getProperty;
import static org.agrona.SystemUtil.getDurationInNanos;
/**
* Minimum multicast sender flow control strategy only for preferred members.
*
* Flow control is set to minimum of tracked preferred receivers.
*
* Tracking of preferred receivers is done as long as they continue to send Status Messages. Once SMs stop, the receiver
* tracking for that receiver will timeout after a given number of nanoseconds.
*/
public class PreferredMulticastFlowControl implements FlowControl
{
/**
* Property name to set timeout, in nanoseconds, for a receiver to be tracked.
*/
public static final String RECEIVER_TIMEOUT_PROP_NAME = "aeron.PreferredMulticastFlowControl.receiverTimeout";
/**
* Default timeout, in nanoseconds, until a receiver is no longer tracked and considered for minimum.
*/
public static final long RECEIVER_TIMEOUT_DEFAULT = TimeUnit.SECONDS.toNanos(2);
public static final long RECEIVER_TIMEOUT = getDurationInNanos(
RECEIVER_TIMEOUT_PROP_NAME, RECEIVER_TIMEOUT_DEFAULT);
/**
* Property name used to set Application Specific Feedback (ASF) in Status Messages to identify preferred receivers.
*/
public static final String PREFERRED_ASF_PROP_NAME = "aeron.PreferredMulticastFlowControl.asf";
/**
* Default Application Specific Feedback (ASF) value
*/
public static final String PREFERRED_ASF_DEFAULT = "FFFFFFFF";
public static final String PREFERRED_ASF = getProperty(PREFERRED_ASF_PROP_NAME, PREFERRED_ASF_DEFAULT);
public static final byte[] PREFERRED_ASF_BYTES = BitUtil.fromHex(PREFERRED_ASF);
private final ArrayList receiverList = new ArrayList<>();
private final byte[] smAsf = new byte[64];
private volatile boolean shouldLinger = true;
/**
* {@inheritDoc}
*/
public long onStatusMessage(
final StatusMessageFlyweight flyweight,
final InetSocketAddress receiverAddress,
final long senderLimit,
final int initialTermId,
final int positionBitsToShift,
final long timeNs)
{
final long position = computePosition(
flyweight.consumptionTermId(),
flyweight.consumptionTermOffset(),
positionBitsToShift,
initialTermId);
final long windowLength = flyweight.receiverWindowLength();
final long receiverId = flyweight.receiverId();
final boolean isFromPreferred = isFromPreferred(flyweight);
final long lastPositionPlusWindow = position + windowLength;
boolean isExisting = false;
long minPosition = Long.MAX_VALUE;
final ArrayList receiverList = this.receiverList;
for (int i = 0, size = receiverList.size(); i < size; i++)
{
final Receiver receiver = receiverList.get(i);
if (isFromPreferred && receiverId == receiver.receiverId)
{
receiver.lastPosition = Math.max(position, receiver.lastPosition);
receiver.lastPositionPlusWindow = lastPositionPlusWindow;
receiver.timeOfLastStatusMessageNs = timeNs;
isExisting = true;
}
minPosition = Math.min(minPosition, receiver.lastPositionPlusWindow);
}
if (isFromPreferred && !isExisting)
{
receiverList.add(new Receiver(position, lastPositionPlusWindow, timeNs, receiverId, receiverAddress));
minPosition = Math.min(minPosition, lastPositionPlusWindow);
}
return receiverList.size() > 0 ?
Math.max(senderLimit, minPosition) :
Math.max(senderLimit, lastPositionPlusWindow);
}
/**
* {@inheritDoc}
*/
public void initialize(final int initialTermId, final int termBufferLength)
{
}
/**
* {@inheritDoc}
*/
public long onIdle(final long timeNs, final long senderLimit, final long senderPosition, final boolean isEos)
{
long minPosition = Long.MAX_VALUE;
long minLimitPosition = Long.MAX_VALUE;
final ArrayList receiverList = this.receiverList;
for (int lastIndex = receiverList.size() - 1, i = lastIndex; i >= 0; i--)
{
final Receiver receiver = receiverList.get(i);
if ((receiver.timeOfLastStatusMessageNs + RECEIVER_TIMEOUT) - timeNs < 0)
{
ArrayListUtil.fastUnorderedRemove(receiverList, i, lastIndex--);
}
else
{
minPosition = Math.min(minPosition, receiver.lastPosition);
minLimitPosition = Math.min(minLimitPosition, receiver.lastPositionPlusWindow);
}
}
if (isEos && shouldLinger)
{
if (0 == receiverList.size() || minPosition >= senderPosition)
{
shouldLinger = false;
}
}
return receiverList.size() > 0 ? minLimitPosition : senderLimit;
}
/**
* {@inheritDoc}
*/
public boolean shouldLinger(final long timeNs)
{
return shouldLinger;
}
public boolean isFromPreferred(final StatusMessageFlyweight statusMessageFlyweight)
{
final int asfLength = statusMessageFlyweight.applicationSpecificFeedback(smAsf);
boolean result = false;
// default ASF is 4 bytes
if (asfLength >= 4)
{
if (smAsf[0] == PREFERRED_ASF_BYTES[0] &&
smAsf[1] == PREFERRED_ASF_BYTES[1] &&
smAsf[2] == PREFERRED_ASF_BYTES[2] &&
smAsf[3] == PREFERRED_ASF_BYTES[3])
{
result = true;
}
}
return result;
}
static class Receiver
{
long lastPosition;
long lastPositionPlusWindow;
long timeOfLastStatusMessageNs;
final long receiverId;
final InetSocketAddress address;
Receiver(
final long lastPosition,
final long lastPositionPlusWindow,
final long timeNs,
final long receiverId,
final InetSocketAddress receiverAddress)
{
this.lastPosition = lastPosition;
this.lastPositionPlusWindow = lastPositionPlusWindow;
this.timeOfLastStatusMessageNs = timeNs;
this.receiverId = receiverId;
this.address = receiverAddress;
}
}
}