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- /*
- * Copyright (C) 2010, Google Inc.
- * and other copyright owners as documented in the project's IP log.
- *
- * This program and the accompanying materials are made available
- * under the terms of the Eclipse Distribution License v1.0 which
- * accompanies this distribution, is reproduced below, and is
- * available at http://www.eclipse.org/org/documents/edl-v10.php
- *
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or
- * without modification, are permitted provided that the following
- * conditions are met:
- *
- * - Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *
- * - Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following
- * disclaimer in the documentation and/or other materials provided
- * with the distribution.
- *
- * - Neither the name of the Eclipse Foundation, Inc. nor the
- * names of its contributors may be used to endorse or promote
- * products derived from this software without specific prior
- * written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
- * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
- * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
- * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
- * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
- * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
- * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
- * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
- * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
- * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
- * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
-
- package org.eclipse.jgit.internal.storage.pack;
-
- import java.io.IOException;
- import java.util.ArrayList;
- import java.util.Collections;
- import java.util.Comparator;
- import java.util.Iterator;
- import java.util.LinkedList;
- import java.util.List;
- import java.util.concurrent.Callable;
-
- import org.eclipse.jgit.lib.ObjectReader;
- import org.eclipse.jgit.lib.ThreadSafeProgressMonitor;
- import org.eclipse.jgit.storage.pack.PackConfig;
-
- final class DeltaTask implements Callable<Object> {
- static final long MAX_METER = 9 << 20;
-
- static final class Block {
- private static final int MIN_TOP_PATH = 50 << 20;
-
- final List<DeltaTask> tasks;
- final int threads;
- final PackConfig config;
- final ObjectReader templateReader;
- final DeltaCache dc;
- final ThreadSafeProgressMonitor pm;
- final ObjectToPack[] list;
- final int beginIndex;
- final int endIndex;
-
- private long totalWeight;
- private long bytesPerUnit;
-
- Block(int threads, PackConfig config, ObjectReader reader,
- DeltaCache dc, ThreadSafeProgressMonitor pm,
- ObjectToPack[] list, int begin, int end) {
- this.tasks = new ArrayList<DeltaTask>(threads);
- this.threads = threads;
- this.config = config;
- this.templateReader = reader;
- this.dc = dc;
- this.pm = pm;
- this.list = list;
- this.beginIndex = begin;
- this.endIndex = end;
- }
-
- int cost() {
- int d = (int) (totalWeight / bytesPerUnit);
- if (totalWeight % bytesPerUnit != 0)
- d++;
- return d;
- }
-
- synchronized DeltaWindow stealWork(DeltaTask forThread) {
- for (;;) {
- DeltaTask maxTask = null;
- Slice maxSlice = null;
- int maxWork = 0;
-
- for (DeltaTask task : tasks) {
- Slice s = task.remaining();
- if (s != null && maxWork < s.size()) {
- maxTask = task;
- maxSlice = s;
- maxWork = s.size();
- }
- }
- if (maxTask == null)
- return null;
- if (maxTask.tryStealWork(maxSlice))
- return forThread.initWindow(maxSlice);
- }
- }
-
- void partitionTasks() {
- ArrayList<WeightedPath> topPaths = computeTopPaths();
- Iterator<WeightedPath> topPathItr = topPaths.iterator();
- int nextTop = 0;
- long weightPerThread = totalWeight / threads;
- for (int i = beginIndex; i < endIndex;) {
- DeltaTask task = new DeltaTask(this);
- long w = 0;
-
- // Assign the thread one top path.
- if (topPathItr.hasNext()) {
- WeightedPath p = topPathItr.next();
- w += p.weight;
- task.add(p.slice);
- }
-
- // Assign the task thread ~average weight.
- int s = i;
- for (; w < weightPerThread && i < endIndex;) {
- if (nextTop < topPaths.size()
- && i == topPaths.get(nextTop).slice.beginIndex) {
- if (s < i)
- task.add(new Slice(s, i));
- s = i = topPaths.get(nextTop++).slice.endIndex;
- } else
- w += list[i++].getWeight();
- }
-
- // Round up the slice to the end of a path.
- if (s < i) {
- int h = list[i - 1].getPathHash();
- while (i < endIndex) {
- if (h == list[i].getPathHash())
- i++;
- else
- break;
- }
- task.add(new Slice(s, i));
- }
- if (!task.slices.isEmpty())
- tasks.add(task);
- }
- while (topPathItr.hasNext()) {
- WeightedPath p = topPathItr.next();
- DeltaTask task = new DeltaTask(this);
- task.add(p.slice);
- tasks.add(task);
- }
-
- topPaths = null;
- }
-
- private ArrayList<WeightedPath> computeTopPaths() {
- ArrayList<WeightedPath> topPaths = new ArrayList<WeightedPath>(
- threads);
- int cp = beginIndex;
- int ch = list[cp].getPathHash();
- long cw = list[cp].getWeight();
- totalWeight = list[cp].getWeight();
-
- for (int i = cp + 1; i < endIndex; i++) {
- ObjectToPack o = list[i];
- if (ch != o.getPathHash()) {
- if (MIN_TOP_PATH < cw) {
- if (topPaths.size() < threads) {
- Slice s = new Slice(cp, i);
- topPaths.add(new WeightedPath(cw, s));
- if (topPaths.size() == threads)
- Collections.sort(topPaths);
- } else if (topPaths.get(0).weight < cw) {
- Slice s = new Slice(cp, i);
- WeightedPath p = new WeightedPath(cw, s);
- topPaths.set(0, p);
- if (p.compareTo(topPaths.get(1)) > 0)
- Collections.sort(topPaths);
- }
- }
- cp = i;
- ch = o.getPathHash();
- cw = 0;
- }
- if (o.isEdge() || o.doNotAttemptDelta())
- continue;
- cw += o.getWeight();
- totalWeight += o.getWeight();
- }
-
- // Sort by starting index to identify gaps later.
- Collections.sort(topPaths, new Comparator<WeightedPath>() {
- public int compare(WeightedPath a, WeightedPath b) {
- return a.slice.beginIndex - b.slice.beginIndex;
- }
- });
-
- bytesPerUnit = 1;
- while (MAX_METER <= (totalWeight / bytesPerUnit))
- bytesPerUnit <<= 10;
- return topPaths;
- }
- }
-
- static final class WeightedPath implements Comparable<WeightedPath> {
- final long weight;
- final Slice slice;
-
- WeightedPath(long weight, Slice s) {
- this.weight = weight;
- this.slice = s;
- }
-
- public int compareTo(WeightedPath o) {
- int cmp = Long.signum(weight - o.weight);
- if (cmp != 0)
- return cmp;
- return slice.beginIndex - o.slice.beginIndex;
- }
- }
-
- static final class Slice {
- final int beginIndex;
- final int endIndex;
-
- Slice(int b, int e) {
- beginIndex = b;
- endIndex = e;
- }
-
- final int size() {
- return endIndex - beginIndex;
- }
- }
-
- private final Block block;
- private final LinkedList<Slice> slices;
-
- private ObjectReader or;
- private DeltaWindow dw;
-
- DeltaTask(Block b) {
- this.block = b;
- this.slices = new LinkedList<Slice>();
- }
-
- void add(Slice s) {
- if (!slices.isEmpty()) {
- Slice last = slices.getLast();
- if (last.endIndex == s.beginIndex) {
- slices.removeLast();
- slices.add(new Slice(last.beginIndex, s.endIndex));
- return;
- }
- }
- slices.add(s);
- }
-
- public Object call() throws Exception {
- or = block.templateReader.newReader();
- try {
- DeltaWindow w;
- for (;;) {
- synchronized (this) {
- if (slices.isEmpty())
- break;
- w = initWindow(slices.removeFirst());
- }
- runWindow(w);
- }
- while ((w = block.stealWork(this)) != null)
- runWindow(w);
- } finally {
- block.pm.endWorker();
- or.release();
- or = null;
- }
- return null;
- }
-
- DeltaWindow initWindow(Slice s) {
- DeltaWindow w = new DeltaWindow(block.config, block.dc,
- or, block.pm, block.bytesPerUnit,
- block.list, s.beginIndex, s.endIndex);
- synchronized (this) {
- dw = w;
- }
- return w;
- }
-
- private void runWindow(DeltaWindow w) throws IOException {
- try {
- w.search();
- } finally {
- synchronized (this) {
- dw = null;
- }
- }
- }
-
- synchronized Slice remaining() {
- if (!slices.isEmpty())
- return slices.getLast();
- DeltaWindow d = dw;
- return d != null ? d.remaining() : null;
- }
-
- synchronized boolean tryStealWork(Slice s) {
- if (!slices.isEmpty() && slices.getLast().beginIndex == s.beginIndex) {
- slices.removeLast();
- return true;
- }
- DeltaWindow d = dw;
- return d != null ? d.tryStealWork(s) : false;
- }
- }
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