Class: Pf2::Reporter::FirefoxProfiler::ThreadReport

Inherits:
Object
  • Object
show all
Defined in:
lib/pf2/reporter/firefox_profiler.rb

Instance Method Summary collapse

Constructor Details

#initialize(thread) ⇒ ThreadReport 



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# File 'lib/pf2/reporter/firefox_profiler.rb', line 61

def initialize(thread)
  @thread = thread

  # Populated in other methods
  @func_id_map = {}
  @frame_id_map = {}
  @stack_tree_id_map = {}

  @string_table = {}
end

Instance Method Details

#array_of_paths_to_tree(paths) ⇒ Object 



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# File 'lib/pf2/reporter/firefox_profiler.rb', line 288

def array_of_paths_to_tree(paths)
  new_stack_tree = { children: {}, node_id: 0, frame_id: 0 }
  paths.each do |path|
    current = new_stack_tree
    path[1..].each do |frame|
      frame_id = frame[:frame_id]
      node_id = frame[:node_id]
      current[:children][frame_id] ||= { children: {}, node_id: node_id, frame_id: frame_id }
      current = current[:children][frame_id]
    end
  end
  new_stack_tree
end

#build_frame_table ⇒ Object 



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# File 'lib/pf2/reporter/firefox_profiler.rb', line 139

def build_frame_table
  ret = {
    address: [],
    category: [],
    subcategory: [],
    func: [],
    inner_window_id: [],
    implementation: [],
    line: [],
    column: [],
    optimizations: [],
    inline_depth: [],
    native_symbol: [],
  }

  @thread[:frames].each.with_index do |(id, frame), i|
    ret[:address] << frame[:address].to_s
    ret[:category] << 1
    ret[:subcategory] << 1
    ret[:func] << i # TODO
    ret[:inner_window_id] << nil
    ret[:implementation] << nil
    ret[:line] << frame[:callsite_lineno]
    ret[:column] << nil
    ret[:optimizations] << nil
    ret[:inline_depth] << 0
    ret[:native_symbol] << nil

    @frame_id_map[id] = i
  end

  ret[:length] = ret[:address].length
  ret
end

#build_func_table ⇒ Object 



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# File 'lib/pf2/reporter/firefox_profiler.rb', line 174

def build_func_table
  ret = {
    name: [],
    is_js: [],
    relevant_for_js: [],
    resource: [],
    file_name: [],
    line_number: [],
    column_number: [],
  }

  @thread[:frames].each.with_index do |(id, frame), i|
    native = (frame[:entry_type] == 'Native')
    label = "#{native ? "Native: " : ""}#{frame[:full_label]}"
    ret[:name] << string_id(label)
    ret[:is_js] << !native
    ret[:relevant_for_js] << false
    ret[:resource] << -1
    ret[:file_name] << string_id(frame[:file_name])
    ret[:line_number] << frame[:function_first_lineno]
    ret[:column_number] << nil

    @func_id_map[id] = i
  end

  ret[:length] = ret[:name].length
  ret
end

#build_samples ⇒ Object 



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# File 'lib/pf2/reporter/firefox_profiler.rb', line 118

def build_samples
  ret = {
    event_delay: [],
    stack: [],
    time: [],
    duration: [],
    # weight: nil,
    # weight_type: 'samples',
  }

  @thread[:samples].each do |sample|
    ret[:stack] << @stack_tree_id_map[sample[:stack_tree_id]]
    ret[:time] << sample[:elapsed_ns] / 1000000 # ns -> ms
    ret[:duration] << 1
    ret[:event_delay] << 0
  end

  ret[:length] = ret[:stack].length
  ret
end

#build_stack_table(func_table, frame_table) ⇒ Object 



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# File 'lib/pf2/reporter/firefox_profiler.rb', line 302

def build_stack_table(func_table, frame_table)
  ret = {
    frame: [],
    category: [],
    subcategory: [],
    prefix: [],
  }

  queue = []

  @thread[:stack_tree][:children].each {|_, c| queue << [nil, c] }

  loop do
    break if queue.size == 0

    prefix, node = queue.shift
    ret[:frame] << @frame_id_map[node[:frame_id]]
    ret[:category] << (build_string_table[func_table[:name][frame_table[:func][@frame_id_map[node[:frame_id]]]]].start_with?('Native:') ? 2 : 1)
    ret[:subcategory] << nil
    ret[:prefix] << prefix

    # The index of this frame - children can refer to this frame using this index as prefix
    frame_index = ret[:frame].length - 1
    @stack_tree_id_map[node[:node_id]] = frame_index

    # Enqueue children nodes
    node[:children].each {|_, c| queue << [frame_index, c] }
  end

  ret[:length] = ret[:frame].length
  ret
end

#build_string_table ⇒ Object 



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# File 'lib/pf2/reporter/firefox_profiler.rb', line 335

def build_string_table
  @string_table.sort_by {|_, v| v}.map {|s| s[0] }
end

#emit ⇒ Object 



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# File 'lib/pf2/reporter/firefox_profiler.rb', line 76

def emit
  x = weave_native_stack(@thread[:stack_tree])
  @thread[:stack_tree] = x
  func_table = build_func_table
  frame_table = build_frame_table
  stack_table = build_stack_table(func_table, frame_table)
  samples = build_samples

  string_table = build_string_table

  {
    process_type: 'default',
    process_name: 'ruby',
    process_startup_time: 0,
    process_shutdown_time: nil,
    register_time: 0,
    unregister_time: nil,
    paused_ranges: [],
    name: "Thread (tid: #{@thread[:thread_id]})",
    is_main_thread: true,
    is_js_tracer: true,
    # FIXME: We can fill the correct PID only after we correctly fill is_main_thread
    # (only one thread could be marked as is_main_thread in a single process)
    pid: @thread[:thread_id],
    tid: @thread[:thread_id],
    samples: samples,
    markers: markers,
    stack_table: stack_table,
    frame_table: frame_table,
    string_array: build_string_table,
    func_table: func_table,
    resource_table: {
      lib: [],
      name: [],
      host: [],
      type: [],
      length: 0,
    },
    native_symbols: [],
  }
end

#inspect ⇒ Object 



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# File 'lib/pf2/reporter/firefox_profiler.rb', line 72

def inspect
  "" # TODO: provide something better
end

#markers ⇒ Object 



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# File 'lib/pf2/reporter/firefox_profiler.rb', line 345

def markers
  {
    data: [],
    name: [],
    time: [],
    start_time: [],
    end_time: [],
    phase: [],
    category: [],
    length: 0
  }
end

#string_id(str) ⇒ Object 



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# File 'lib/pf2/reporter/firefox_profiler.rb', line 339

def string_id(str)
  return @string_table[str] if @string_table.has_key?(str)
  @string_table[str] = @string_table.length
  @string_table[str]
end

#tree_to_array_of_paths(stack_tree, frames, path, collected_paths) ⇒ Object 



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# File 'lib/pf2/reporter/firefox_profiler.rb', line 277

def tree_to_array_of_paths(stack_tree, frames, path, collected_paths)
  new_path = path + [{ frame_id: stack_tree[:frame_id], node_id: stack_tree[:node_id] }]
  if stack_tree[:children].empty?
    collected_paths << new_path
  else
    stack_tree[:children].each do |frame_id, child|
      tree_to_array_of_paths(child, frames, new_path, collected_paths)
    end
  end
end

#weave_native_stack(stack_tree) ⇒ Object

“Weave” the native stack into the Ruby stack.

Strategy:

  • Split the stack into Ruby and Native parts

  • Start from the root of the Native stack

  • Dig in to the native stack until we hit a rb_vm_exec(), which marks a call into Ruby code

  • Switch to Ruby stack. Keep digging until we hit a Cfunc call, then switch back to Native stack

  • Repeat until we consume the entire stack



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# File 'lib/pf2/reporter/firefox_profiler.rb', line 211

def weave_native_stack(stack_tree)
  collected_paths = []
  tree_to_array_of_paths(stack_tree, @thread[:frames], [], collected_paths)
  collected_paths = collected_paths.map do |path|
    next if path.size == 0

    new_path = []
    new_path << path.shift # root

    # Split the stack into Ruby and Native parts
    native_path, ruby_path = path.partition do |frame|
      frame_id = frame[:frame_id]
      @thread[:frames][frame_id][:entry_type] == 'Native'
    end

    mode = :native

    loop do
      break if ruby_path.size == 0 && native_path.size == 0

      case mode
      when :ruby
        if ruby_path.size == 0
          mode = :native
          next
        end

        next_node = ruby_path[0]
        new_path << ruby_path.shift
        next_node_frame = @thread[:frames][next_node[:frame_id]]
        if native_path.size > 0
          # Search the remainder of the native stack for the same address
          # Note: This isn't a very efficient way for the job... but it still works
          ruby_addr = next_node_frame[:address]
          native_path[0..].each do |native_node|
            native_addr = @thread[:frames][native_node[:frame_id]][:address]
            if ruby_addr && native_addr && ruby_addr == native_addr
              # A match has been found. Switch to native mode
              mode = :native
              break
            end
          end
        end
      when :native
        if native_path.size == 0
          mode = :ruby
          next
        end

        # Dig until we meet a rb_vm_exec
        next_node = native_path[0]
        new_path << native_path.shift
        if @thread[:frames][next_node[:frame_id]][:full_label] =~ /vm_exec_core/ # VM_EXEC in vm_exec.h
          mode = :ruby
        end
      end
    end

    new_path
  end

  # reconstruct stack_tree
  new_stack_tree = array_of_paths_to_tree(collected_paths)
  new_stack_tree
end