DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Implementation

Mercurial (b6d82b1a6b02)

VCS Links

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 * vim: set ts=8 sts=2 et sw=2 tw=80:
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef TraceLoggingGraph_h
#define TraceLoggingGraph_h

#include "mozilla/MemoryReporting.h"
#include "mozilla/TimeStamp.h"

#include "js/TypeDecls.h"
#include "vm/MutexIDs.h"
#include "vm/TraceLoggingTypes.h"

// clang-format off
/*
 * The output of a tracelogging session is saved in /tmp/tl-data.json.
 * The format of that file is a JS array per tracelogger (=thread), with a map
 * containing:
 *  - dict:   Name of the file containing a json table with the log text.
 *            All other files only contain a index to this table when logging.
 *  - events: Name of the file containing a flat list of log events saved
 *            in binary format.
 *            (64bit: Time Stamp Counter, 32bit index to dict)
 *  - tree:   Name of the file containing the events with duration. The content
 *            is already in a tree data structure. This is also saved in a
 *            binary file.
 *  - treeFormat: The format used to encode the tree. By default "64,64,31,1,32".
 *                There are currently no other formats to save the tree.
 *     - 64,64,31,1,32 signifies how many bytes are used for the different
 *       parts of the tree.
 *       => 64 bits: Time Stamp Counter of start of event.
 *       => 64 bits: Time Stamp Counter of end of event.
 *       => 31 bits: Index to dict file containing the log text.
 *       =>  1 bit:  Boolean signifying if this entry has children.
 *                   When true, the child can be found just right after this
 *                   entry.
 *       => 32 bits: Containing the ID of the next event on the same depth
 *                   or 0 if there isn't an event on the same depth anymore.
 *
 *        /-> The position in the file. Id is this divided by size of entry.
 *        |   So in this case this would be 1 (192bits per entry).
 *        |                              /-> Indicates there are children. The
 *        |                              |   first child is located at current
 *        |                              |   ID + 1. So 1 + 1 in this case: 2.
 *        |                              |   Or 0x00180 in the tree file.
 *        |                              | /-> Next event on the same depth is
 *        |                              | |    located at 4. So 0x00300 in the
 *        |                              | |    tree file.
 *       0x0000C0: [start, end, dictId, 1, 4]
 *
 *
 *       Example:
 *                          0x0: [start, end, dictId, 1, 0]
 *                                        |
 *                      /----------------------------------\
 *                      |                                  |
 *       0xC0: [start, end, dictId, 0, 2]      0x180 [start, end, dictId, 1, 0]
 *                                                      |
 *                                  /----------------------------------\
 *                                  |                                  |
 *         0x240: [start, end, dictId, 0, 4]    0x300 [start, end, dictId, 0, 0]
 */
// clang-format on

namespace js {
void DestroyTraceLoggerGraphState();
size_t SizeOfTraceLogGraphState(mozilla::MallocSizeOf mallocSizeOf);
}  // namespace js

class TraceLoggerGraphState {
  uint32_t numLoggers;
  uint32_t pid_;

  // File pointer to the "tl-data.json" file. (Explained above).
  FILE* out;

#ifdef DEBUG
  bool initialized;
#endif

 public:
  js::Mutex lock;

 public:
  TraceLoggerGraphState()
      : numLoggers(0),
        pid_(0),
        out(nullptr)
#ifdef DEBUG
        ,
        initialized(false)
#endif
        ,
        lock(js::mutexid::TraceLoggerGraphState) {
  }

  bool init();
  ~TraceLoggerGraphState();

  uint32_t nextLoggerId();
  uint32_t pid() { return pid_; }

  size_t sizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf) const;
  size_t sizeOfIncludingThis(mozilla::MallocSizeOf mallocSizeOf) const {
    return mallocSizeOf(this) + sizeOfExcludingThis(mallocSizeOf);
  }
};

namespace js {
class TraceLoggerThread;
}  // namespace js

class TraceLoggerGraph {
  // This is needed so that we can write the data to the JSON writer from the TL
  // thread class.
  friend class js::TraceLoggerThread;

 private:
  // The layout of the tree in memory and in the log file. Readable by JS
  // using TypedArrays.
  struct TreeEntry {
    uint64_t start_;
    uint64_t stop_;
    union {
      struct {
        uint32_t textId_ : 31;
        uint32_t hasChildren_ : 1;
      } s;
      uint32_t value_;
    } u;
    uint32_t nextId_;

    TreeEntry(uint64_t start, uint64_t stop, uint32_t textId, bool hasChildren,
              uint32_t nextId) {
      start_ = start;
      stop_ = stop;
      u.s.textId_ = textId;
      u.s.hasChildren_ = hasChildren;
      nextId_ = nextId;
    }
    TreeEntry() : start_(0), stop_(0), u{}, nextId_(0) {}
    uint64_t start() { return start_; }
    uint64_t stop() { return stop_; }
    uint32_t textId() { return u.s.textId_; }
    bool hasChildren() { return u.s.hasChildren_; }
    uint32_t nextId() { return nextId_; }
    void setStart(uint64_t start) { start_ = start; }
    void setStop(uint64_t stop) { stop_ = stop; }
    void setTextId(uint32_t textId) {
      MOZ_ASSERT(textId < uint32_t(1 << 31));
      u.s.textId_ = textId;
    }
    void setHasChildren(bool hasChildren) { u.s.hasChildren_ = hasChildren; }
    void setNextId(uint32_t nextId) { nextId_ = nextId; }
  };

  // Helper structure for keeping track of the current entries in
  // the tree. Pushed by `start(id)`, popped by `stop(id)`. The active flag
  // is used to know if a subtree doesn't need to get logged.
  struct StackEntry {
    uint32_t treeId_;
    uint32_t lastChildId_;
    struct {
      uint32_t textId_ : 31;
      uint32_t active_ : 1;
    } s;
    StackEntry(uint32_t treeId, uint32_t lastChildId, bool active = true)
        : treeId_(treeId), lastChildId_(lastChildId) {
      s.textId_ = 0;
      s.active_ = active;
    }
    uint32_t treeId() { return treeId_; }
    uint32_t lastChildId() { return lastChildId_; }
    uint32_t textId() { return s.textId_; }
    bool active() { return s.active_; }
    void setTreeId(uint32_t treeId) { treeId_ = treeId; }
    void setLastChildId(uint32_t lastChildId) { lastChildId_ = lastChildId; }
    void setTextId(uint32_t textId) {
      MOZ_ASSERT(textId < uint32_t(1 << 31));
      s.textId_ = textId;
    }
    void setActive(bool active) { s.active_ = active; }
  };

 public:
  TraceLoggerGraph() {}
  ~TraceLoggerGraph();

  bool init(uint64_t timestamp, bool graphFileEnabled);

  // Link a textId with a particular text.
  void addTextId(uint32_t id, const char* text);
  void addTextId(uint32_t id, const char* text, mozilla::Maybe<uint32_t>& line,
                 mozilla::Maybe<uint32_t>& column);

  // Create a tree out of all the given events.
  void log(ContinuousSpace<EventEntry>& events, mozilla::TimeStamp startTime);

  static size_t treeSizeFlushLimit() {
    // Allow tree size to grow to 100MB.
    return 100 * 1024 * 1024 / sizeof(TreeEntry);
  }

  uint32_t nextTextId() { return nextTextId_; }

  size_t sizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf) const;
  size_t sizeOfIncludingThis(mozilla::MallocSizeOf mallocSizeOf) const;

 private:
  bool failed = false;
  bool enabled = false;
  uint32_t nextTextId_ = 0;

  FILE* dictFile = nullptr;
  FILE* treeFile = nullptr;
  FILE* eventFile = nullptr;

  ContinuousSpace<TreeEntry> tree;
  ContinuousSpace<StackEntry> stack;
  uint32_t treeOffset = 0;

  // Helper functions that convert a TreeEntry in different endianness
  // in place.
  void entryToBigEndian(TreeEntry* entry);
  void entryToSystemEndian(TreeEntry* entry);

  // Helper functions to get/save a tree from file.
  bool getTreeEntry(uint32_t treeId, TreeEntry* entry);
  bool saveTreeEntry(uint32_t treeId, TreeEntry* entry);

  // Return the first StackEntry that is active.
  StackEntry& getActiveAncestor();

  // This contains the meat of startEvent, except the test for enough space,
  // the test if tracelogger is enabled and the timestamp computation.
  void startEvent(uint32_t id, uint64_t timestamp);
  bool startEventInternal(uint32_t id, uint64_t timestamp);

  // Update functions that can adjust the items in the tree,
  // both in memory or already written to disk.
  bool updateHasChildren(uint32_t treeId, bool hasChildren = true);
  bool updateNextId(uint32_t treeId, uint32_t nextId);
  bool updateStop(uint32_t treeId, uint64_t timestamp);

  // Flush the tree.
  bool flush();

  // Stop a tree event.
  void stopEvent(uint32_t id, uint64_t timestamp);
  void stopEvent(uint64_t timestamp);

  // Log an (non-tree) event.
  void logTimestamp(uint32_t id, uint64_t timestamp);

  // Disable logging and forcefully report all not yet stopped tree events
  // as stopped.
  void disable(uint64_t timestamp);
};

#endif /* TraceLoggingGraph_h */