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      1 //
      2 // Copyright (C) 2010 The Android Open Source Project
      3 //
      4 // Licensed under the Apache License, Version 2.0 (the "License");
      5 // you may not use this file except in compliance with the License.
      6 // You may obtain a copy of the License at
      7 //
      8 //      http://www.apache.org/licenses/LICENSE-2.0
      9 //
     10 // Unless required by applicable law or agreed to in writing, software
     11 // distributed under the License is distributed on an "AS IS" BASIS,
     12 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13 // See the License for the specific language governing permissions and
     14 // limitations under the License.
     15 //
     16 
     17 #include "update_engine/payload_generator/cycle_breaker.h"
     18 
     19 #include <set>
     20 #include <string>
     21 #include <utility>
     22 #include <vector>
     23 
     24 #include <base/logging.h>
     25 #include <gtest/gtest.h>
     26 
     27 #include "update_engine/common/utils.h"
     28 #include "update_engine/payload_generator/graph_types.h"
     29 
     30 using std::make_pair;
     31 using std::pair;
     32 using std::set;
     33 using std::string;
     34 using std::vector;
     35 
     36 namespace chromeos_update_engine {
     37 
     38 namespace {
     39 void SetOpForNodes(Graph* graph) {
     40   for (Vertex& vertex : *graph) {
     41     vertex.aop.op.set_type(InstallOperation::MOVE);
     42   }
     43 }
     44 }  // namespace
     45 
     46 class CycleBreakerTest : public ::testing::Test {};
     47 
     48 TEST(CycleBreakerTest, SimpleTest) {
     49   int counter = 0;
     50   const Vertex::Index n_a = counter++;
     51   const Vertex::Index n_b = counter++;
     52   const Vertex::Index n_c = counter++;
     53   const Vertex::Index n_d = counter++;
     54   const Vertex::Index n_e = counter++;
     55   const Vertex::Index n_f = counter++;
     56   const Vertex::Index n_g = counter++;
     57   const Vertex::Index n_h = counter++;
     58   const Graph::size_type kNodeCount = counter++;
     59 
     60   Graph graph(kNodeCount);
     61   SetOpForNodes(&graph);
     62 
     63   graph[n_a].out_edges.insert(make_pair(n_e, EdgeProperties()));
     64   graph[n_a].out_edges.insert(make_pair(n_f, EdgeProperties()));
     65   graph[n_b].out_edges.insert(make_pair(n_a, EdgeProperties()));
     66   graph[n_c].out_edges.insert(make_pair(n_d, EdgeProperties()));
     67   graph[n_d].out_edges.insert(make_pair(n_e, EdgeProperties()));
     68   graph[n_d].out_edges.insert(make_pair(n_f, EdgeProperties()));
     69   graph[n_e].out_edges.insert(make_pair(n_b, EdgeProperties()));
     70   graph[n_e].out_edges.insert(make_pair(n_c, EdgeProperties()));
     71   graph[n_e].out_edges.insert(make_pair(n_f, EdgeProperties()));
     72   graph[n_f].out_edges.insert(make_pair(n_g, EdgeProperties()));
     73   graph[n_g].out_edges.insert(make_pair(n_h, EdgeProperties()));
     74   graph[n_h].out_edges.insert(make_pair(n_g, EdgeProperties()));
     75 
     76   CycleBreaker breaker;
     77 
     78   set<Edge> broken_edges;
     79   breaker.BreakCycles(graph, &broken_edges);
     80 
     81   // The following cycles must be cut:
     82   // A->E->B
     83   // C->D->E
     84   // G->H
     85 
     86   EXPECT_TRUE(utils::SetContainsKey(broken_edges, make_pair(n_a, n_e)) ||
     87               utils::SetContainsKey(broken_edges, make_pair(n_e, n_b)) ||
     88               utils::SetContainsKey(broken_edges, make_pair(n_b, n_a)));
     89   EXPECT_TRUE(utils::SetContainsKey(broken_edges, make_pair(n_c, n_d)) ||
     90               utils::SetContainsKey(broken_edges, make_pair(n_d, n_e)) ||
     91               utils::SetContainsKey(broken_edges, make_pair(n_e, n_c)));
     92   EXPECT_TRUE(utils::SetContainsKey(broken_edges, make_pair(n_g, n_h)) ||
     93               utils::SetContainsKey(broken_edges, make_pair(n_h, n_g)));
     94   EXPECT_EQ(3U, broken_edges.size());
     95 }
     96 
     97 namespace {
     98 pair<Vertex::Index, EdgeProperties> EdgeWithWeight(Vertex::Index dest,
     99 uint64_t weight) {
    100   EdgeProperties props;
    101   props.extents.resize(1);
    102   props.extents[0].set_num_blocks(weight);
    103   return make_pair(dest, props);
    104 }
    105 }  // namespace
    106 
    107 
    108 // This creates a bunch of cycles like this:
    109 //
    110 //               root <------.
    111 //    (t)->     / | \        |
    112 //             V  V  V       |
    113 //             N  N  N       |
    114 //              \ | /        |
    115 //               VVV         |
    116 //                N          |
    117 //              / | \        |
    118 //             V  V  V       |
    119 //             N  N  N       |
    120 //               ...         |
    121 //     (s)->    \ | /        |
    122 //               VVV         |
    123 //                N          |
    124 //                 \_________/
    125 //
    126 // such that the original cutting algo would cut edges (s). We changed
    127 // the algorithm to cut cycles (t) instead, since they are closer to the
    128 // root, and that can massively speed up cycle cutting.
    129 TEST(CycleBreakerTest, AggressiveCutTest) {
    130   size_t counter = 0;
    131 
    132   const int kNodesPerGroup = 4;
    133   const int kGroups = 33;
    134 
    135   Graph graph(kGroups * kNodesPerGroup + 1);  // + 1 for the root node
    136   SetOpForNodes(&graph);
    137 
    138   const Vertex::Index n_root = counter++;
    139 
    140   Vertex::Index last_hub = n_root;
    141   for (int i = 0; i < kGroups; i++) {
    142     uint64_t weight = 5;
    143     if (i == 0)
    144       weight = 2;
    145     else if (i == (kGroups - 1))
    146       weight = 1;
    147 
    148     const Vertex::Index next_hub = counter++;
    149 
    150     for (int j = 0; j < (kNodesPerGroup - 1); j++) {
    151       const Vertex::Index node = counter++;
    152       graph[last_hub].out_edges.insert(EdgeWithWeight(node, weight));
    153       graph[node].out_edges.insert(EdgeWithWeight(next_hub, weight));
    154     }
    155     last_hub = next_hub;
    156   }
    157 
    158   graph[last_hub].out_edges.insert(EdgeWithWeight(n_root, 5));
    159 
    160   EXPECT_EQ(counter, graph.size());
    161 
    162   CycleBreaker breaker;
    163 
    164   set<Edge> broken_edges;
    165   LOG(INFO) << "If this hangs for more than 1 second, the test has failed.";
    166   breaker.BreakCycles(graph, &broken_edges);
    167 
    168   set<Edge> expected_cuts;
    169 
    170   for (Vertex::EdgeMap::const_iterator it = graph[n_root].out_edges.begin(),
    171        e = graph[n_root].out_edges.end(); it != e; ++it) {
    172     expected_cuts.insert(make_pair(n_root, it->first));
    173   }
    174 
    175   EXPECT_TRUE(broken_edges == expected_cuts);
    176 }
    177 
    178 TEST(CycleBreakerTest, WeightTest) {
    179   size_t counter = 0;
    180   const Vertex::Index n_a = counter++;
    181   const Vertex::Index n_b = counter++;
    182   const Vertex::Index n_c = counter++;
    183   const Vertex::Index n_d = counter++;
    184   const Vertex::Index n_e = counter++;
    185   const Vertex::Index n_f = counter++;
    186   const Vertex::Index n_g = counter++;
    187   const Vertex::Index n_h = counter++;
    188   const Vertex::Index n_i = counter++;
    189   const Vertex::Index n_j = counter++;
    190   const Graph::size_type kNodeCount = counter++;
    191 
    192   Graph graph(kNodeCount);
    193   SetOpForNodes(&graph);
    194 
    195   graph[n_a].out_edges.insert(EdgeWithWeight(n_b, 4));
    196   graph[n_a].out_edges.insert(EdgeWithWeight(n_f, 3));
    197   graph[n_a].out_edges.insert(EdgeWithWeight(n_h, 2));
    198   graph[n_b].out_edges.insert(EdgeWithWeight(n_a, 3));
    199   graph[n_b].out_edges.insert(EdgeWithWeight(n_c, 4));
    200   graph[n_c].out_edges.insert(EdgeWithWeight(n_b, 5));
    201   graph[n_c].out_edges.insert(EdgeWithWeight(n_d, 3));
    202   graph[n_d].out_edges.insert(EdgeWithWeight(n_a, 6));
    203   graph[n_d].out_edges.insert(EdgeWithWeight(n_e, 3));
    204   graph[n_e].out_edges.insert(EdgeWithWeight(n_d, 4));
    205   graph[n_e].out_edges.insert(EdgeWithWeight(n_g, 5));
    206   graph[n_f].out_edges.insert(EdgeWithWeight(n_g, 2));
    207   graph[n_g].out_edges.insert(EdgeWithWeight(n_f, 3));
    208   graph[n_g].out_edges.insert(EdgeWithWeight(n_d, 5));
    209   graph[n_h].out_edges.insert(EdgeWithWeight(n_i, 8));
    210   graph[n_i].out_edges.insert(EdgeWithWeight(n_e, 4));
    211   graph[n_i].out_edges.insert(EdgeWithWeight(n_h, 9));
    212   graph[n_i].out_edges.insert(EdgeWithWeight(n_j, 6));
    213 
    214   CycleBreaker breaker;
    215 
    216   set<Edge> broken_edges;
    217   breaker.BreakCycles(graph, &broken_edges);
    218 
    219   // These are required to be broken:
    220   EXPECT_TRUE(utils::SetContainsKey(broken_edges, make_pair(n_b, n_a)));
    221   EXPECT_TRUE(utils::SetContainsKey(broken_edges, make_pair(n_b, n_c)));
    222   EXPECT_TRUE(utils::SetContainsKey(broken_edges, make_pair(n_d, n_e)));
    223   EXPECT_TRUE(utils::SetContainsKey(broken_edges, make_pair(n_f, n_g)));
    224   EXPECT_TRUE(utils::SetContainsKey(broken_edges, make_pair(n_h, n_i)));
    225 }
    226 
    227 TEST(CycleBreakerTest, UnblockGraphTest) {
    228   size_t counter = 0;
    229   const Vertex::Index n_a = counter++;
    230   const Vertex::Index n_b = counter++;
    231   const Vertex::Index n_c = counter++;
    232   const Vertex::Index n_d = counter++;
    233   const Graph::size_type kNodeCount = counter++;
    234 
    235   Graph graph(kNodeCount);
    236   SetOpForNodes(&graph);
    237 
    238   graph[n_a].out_edges.insert(EdgeWithWeight(n_b, 1));
    239   graph[n_a].out_edges.insert(EdgeWithWeight(n_c, 1));
    240   graph[n_b].out_edges.insert(EdgeWithWeight(n_c, 2));
    241   graph[n_c].out_edges.insert(EdgeWithWeight(n_b, 2));
    242   graph[n_b].out_edges.insert(EdgeWithWeight(n_d, 2));
    243   graph[n_d].out_edges.insert(EdgeWithWeight(n_a, 2));
    244 
    245   CycleBreaker breaker;
    246 
    247   set<Edge> broken_edges;
    248   breaker.BreakCycles(graph, &broken_edges);
    249 
    250   // These are required to be broken:
    251   EXPECT_TRUE(utils::SetContainsKey(broken_edges, make_pair(n_a, n_b)));
    252   EXPECT_TRUE(utils::SetContainsKey(broken_edges, make_pair(n_a, n_c)));
    253 }
    254 
    255 TEST(CycleBreakerTest, SkipOpsTest) {
    256   size_t counter = 0;
    257   const Vertex::Index n_a = counter++;
    258   const Vertex::Index n_b = counter++;
    259   const Vertex::Index n_c = counter++;
    260   const Graph::size_type kNodeCount = counter++;
    261 
    262   Graph graph(kNodeCount);
    263   SetOpForNodes(&graph);
    264   graph[n_a].aop.op.set_type(InstallOperation::REPLACE_BZ);
    265   graph[n_c].aop.op.set_type(InstallOperation::REPLACE);
    266 
    267   graph[n_a].out_edges.insert(EdgeWithWeight(n_b, 1));
    268   graph[n_c].out_edges.insert(EdgeWithWeight(n_b, 1));
    269 
    270   CycleBreaker breaker;
    271 
    272   set<Edge> broken_edges;
    273   breaker.BreakCycles(graph, &broken_edges);
    274 
    275   EXPECT_EQ(2U, breaker.skipped_ops());
    276 }
    277 
    278 }  // namespace chromeos_update_engine
    279