Examples with BlockingBackChannel org.apache.flink.runtime.iterative.concurrent.BlockingBackChannel used on opensource projects

Example 1 with BlockingBackChannel

use of org.apache.flink.runtime.iterative.concurrent.BlockingBackChannel in project flink by apache.

the class IterationHeadTask method initBackChannel.

/**
 * The iteration head prepares the backchannel: it allocates memory, instantiates a {@link
 * BlockingBackChannel} and hands it to the iteration tail via a {@link Broker} singleton.
 */
private BlockingBackChannel initBackChannel() throws Exception {
    /* get the size of the memory available to the backchannel */
    int backChannelMemoryPages = getMemoryManager().computeNumberOfPages(this.config.getRelativeBackChannelMemory());
    /* allocate the memory available to the backchannel */
    List<MemorySegment> segments = new ArrayList<MemorySegment>();
    int segmentSize = getMemoryManager().getPageSize();
    getMemoryManager().allocatePages(this, segments, backChannelMemoryPages);
    /* instantiate the backchannel */
    BlockingBackChannel backChannel = new BlockingBackChannel(new SerializedUpdateBuffer(segments, segmentSize, getIOManager()));
    /* hand the backchannel over to the iteration tail */
    Broker<BlockingBackChannel> broker = BlockingBackChannelBroker.instance();
    broker.handIn(brokerKey(), backChannel);
    return backChannel;
}

Example 2 with BlockingBackChannel

use of org.apache.flink.runtime.iterative.concurrent.BlockingBackChannel in project flink by apache.

the class IterationHeadTask method run.

@Override
public void run() throws Exception {
    final String brokerKey = brokerKey();
    final int workerIndex = getEnvironment().getTaskInfo().getIndexOfThisSubtask();
    final boolean objectSolutionSet = config.isSolutionSetUnmanaged();
    // if workset iteration
    CompactingHashTable<X> solutionSet = null;
    JoinHashMap<X> solutionSetObjectMap = // if workset iteration with unmanaged solution set
    null;
    boolean waitForSolutionSetUpdate = config.getWaitForSolutionSetUpdate();
    boolean isWorksetIteration = config.getIsWorksetIteration();
    try {
        /* used for receiving the current iteration result from iteration tail */
        SuperstepKickoffLatch nextStepKickoff = new SuperstepKickoffLatch();
        SuperstepKickoffLatchBroker.instance().handIn(brokerKey, nextStepKickoff);
        BlockingBackChannel backChannel = initBackChannel();
        SuperstepBarrier barrier = initSuperstepBarrier();
        SolutionSetUpdateBarrier solutionSetUpdateBarrier = null;
        feedbackDataInput = config.getIterationHeadPartialSolutionOrWorksetInputIndex();
        feedbackTypeSerializer = this.getInputSerializer(feedbackDataInput);
        excludeFromReset(feedbackDataInput);
        int initialSolutionSetInput;
        if (isWorksetIteration) {
            initialSolutionSetInput = config.getIterationHeadSolutionSetInputIndex();
            solutionTypeSerializer = config.getSolutionSetSerializer(getUserCodeClassLoader());
            // setup the index for the solution set
            @SuppressWarnings("unchecked") MutableObjectIterator<X> solutionSetInput = (MutableObjectIterator<X>) createInputIterator(inputReaders[initialSolutionSetInput], solutionTypeSerializer);
            // read the initial solution set
            if (objectSolutionSet) {
                solutionSetObjectMap = initJoinHashMap();
                readInitialSolutionSet(solutionSetObjectMap, solutionSetInput);
                SolutionSetBroker.instance().handIn(brokerKey, solutionSetObjectMap);
            } else {
                solutionSet = initCompactingHashTable();
                readInitialSolutionSet(solutionSet, solutionSetInput);
                SolutionSetBroker.instance().handIn(brokerKey, solutionSet);
            }
            if (waitForSolutionSetUpdate) {
                solutionSetUpdateBarrier = new SolutionSetUpdateBarrier();
                SolutionSetUpdateBarrierBroker.instance().handIn(brokerKey, solutionSetUpdateBarrier);
            }
        } else {
            // bulk iteration case
            @SuppressWarnings("unchecked") TypeSerializerFactory<X> solSer = (TypeSerializerFactory<X>) feedbackTypeSerializer;
            solutionTypeSerializer = solSer;
            // = termination Criterion tail
            if (waitForSolutionSetUpdate) {
                solutionSetUpdateBarrier = new SolutionSetUpdateBarrier();
                SolutionSetUpdateBarrierBroker.instance().handIn(brokerKey, solutionSetUpdateBarrier);
            }
        }
        // instantiate all aggregators and register them at the iteration global registry
        RuntimeAggregatorRegistry aggregatorRegistry = new RuntimeAggregatorRegistry(config.getIterationAggregators(getUserCodeClassLoader()));
        IterationAggregatorBroker.instance().handIn(brokerKey, aggregatorRegistry);
        DataInputView superstepResult = null;
        while (this.running && !terminationRequested()) {
            if (log.isInfoEnabled()) {
                log.info(formatLogString("starting iteration [" + currentIteration() + "]"));
            }
            barrier.setup();
            if (waitForSolutionSetUpdate) {
                solutionSetUpdateBarrier.setup();
            }
            if (!inFirstIteration()) {
                feedBackSuperstepResult(superstepResult);
            }
            super.run();
            // signal to connected tasks that we are done with the superstep
            sendEndOfSuperstepToAllIterationOutputs();
            if (waitForSolutionSetUpdate) {
                solutionSetUpdateBarrier.waitForSolutionSetUpdate();
            }
            // blocking call to wait for the result
            superstepResult = backChannel.getReadEndAfterSuperstepEnded();
            if (log.isInfoEnabled()) {
                log.info(formatLogString("finishing iteration [" + currentIteration() + "]"));
            }
            sendEventToSync(new WorkerDoneEvent(workerIndex, aggregatorRegistry.getAllAggregators()));
            if (log.isInfoEnabled()) {
                log.info(formatLogString("waiting for other workers in iteration [" + currentIteration() + "]"));
            }
            barrier.waitForOtherWorkers();
            if (barrier.terminationSignaled()) {
                if (log.isInfoEnabled()) {
                    log.info(formatLogString("head received termination request in iteration [" + currentIteration() + "]"));
                }
                requestTermination();
                nextStepKickoff.signalTermination();
            } else {
                incrementIterationCounter();
                String[] globalAggregateNames = barrier.getAggregatorNames();
                Value[] globalAggregates = barrier.getAggregates();
                aggregatorRegistry.updateGlobalAggregatesAndReset(globalAggregateNames, globalAggregates);
                nextStepKickoff.triggerNextSuperstep();
            }
        }
        if (log.isInfoEnabled()) {
            log.info(formatLogString("streaming out final result after [" + currentIteration() + "] iterations"));
        }
        if (isWorksetIteration) {
            if (objectSolutionSet) {
                streamSolutionSetToFinalOutput(solutionSetObjectMap);
            } else {
                streamSolutionSetToFinalOutput(solutionSet);
            }
        } else {
            streamOutFinalOutputBulk(new InputViewIterator<X>(superstepResult, this.solutionTypeSerializer.getSerializer()));
        }
        this.finalOutputCollector.close();
    } finally {
        // make sure we unregister everything from the broker:
        // - backchannel
        // - aggregator registry
        // - solution set index
        IterationAggregatorBroker.instance().remove(brokerKey);
        BlockingBackChannelBroker.instance().remove(brokerKey);
        SuperstepKickoffLatchBroker.instance().remove(brokerKey);
        SolutionSetBroker.instance().remove(brokerKey);
        SolutionSetUpdateBarrierBroker.instance().remove(brokerKey);
        if (solutionSet != null) {
            solutionSet.close();
        }
    }
}