edu.mit.streamjit.impl.compiler2.FullDataParallelAllocationStrategy.java Source code

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/*
 * Copyright (c) 2013-2014 Massachusetts Institute of Technology
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
package edu.mit.streamjit.impl.compiler2;

import static com.google.common.base.Preconditions.checkArgument;
import com.google.common.collect.Range;
import com.google.common.math.IntMath;
import edu.mit.streamjit.api.Worker;
import edu.mit.streamjit.impl.common.Configuration;
import java.math.RoundingMode;
import java.util.List;
import java.util.Set;

/**
 * An allocation strategy that fully data-parallelizes over up to N cores.
 * @author Jeffrey Bosboom <jbosboom@csail.mit.edu>
 * @since 12/31/2013
 */
public final class FullDataParallelAllocationStrategy implements AllocationStrategy {
    private final int maxNumCores;

    public FullDataParallelAllocationStrategy(int maxNumCores) {
        checkArgument(maxNumCores >= 1);
        this.maxNumCores = maxNumCores;
    }

    @Override
    public int maxNumCores() {
        return maxNumCores;
    }

    @Override
    public void makeParameters(Set<Worker<?, ?>> workers, Configuration.Builder builder) {
        //no parameters necessary
    }

    @Override
    public void allocateGroup(ActorGroup group, Range<Integer> iterations, List<Core> cores, Configuration config) {
        int coresSize = Math.min(cores.size(), maxNumCores);
        int perCore = IntMath.divide(iterations.upperEndpoint() - iterations.lowerEndpoint(), coresSize,
                RoundingMode.CEILING);
        for (int i = 0; i < coresSize && !iterations.isEmpty(); ++i) {
            int min = iterations.lowerEndpoint();
            Range<Integer> allocation = group.isStateful() ? iterations
                    : iterations.intersection(Range.closedOpen(min, min + perCore));
            cores.get(i).allocate(group, allocation);
            iterations = Range.closedOpen(allocation.upperEndpoint(), iterations.upperEndpoint());
        }
        assert iterations.isEmpty();
    }
}