summaryrefslogtreecommitdiff
path: root/yjit.rb
blob: 3592e20a7fdd929414e65b16f78a522371080f71 (plain)
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
264
265
266
267
268
# This module allows for introspection on YJIT, CRuby's experimental in-process
# just-in-time compiler. This module is for development purposes only;
# everything in this module is highly implementation specific and comes with no
# API stability guarantee whatsoever.
#
# This module is only defined when YJIT has support for the particular platform
# on which CRuby is built.
module RubyVM::YJIT
  if defined?(Disasm)
    def self.disasm(iseq, tty: $stdout && $stdout.tty?)
      iseq = RubyVM::InstructionSequence.of(iseq)

      blocks = blocks_for(iseq)
      return if blocks.empty?

      str = String.new
      str << iseq.disasm
      str << "\n"

      # Sort the blocks by increasing addresses
      sorted_blocks = blocks.sort_by(&:address)

      highlight = ->(str) {
        if tty
          "\x1b[1m#{str}\x1b[0m"
        else
          str
        end
      }

      cs = Disasm.new
      sorted_blocks.each_with_index do |block, i|
        str << "== BLOCK #{i+1}/#{blocks.length}: #{block.code.length} BYTES, ISEQ RANGE [#{block.iseq_start_index},#{block.iseq_end_index}) ".ljust(80, "=")
        str << "\n"

        comments = comments_for(block.address, block.address + block.code.length)
        comment_idx = 0
        cs.disasm(block.code, block.address).each do |i|
          while (comment = comments[comment_idx]) && comment.address <= i.address
            str << "  ; #{highlight.call(comment.comment)}\n"
            comment_idx += 1
          end

          str << sprintf(
            "  %<address>08x:  %<instruction>s\t%<details>s\n",
            address: i.address,
            instruction: i.mnemonic,
            details: i.op_str
          )
        end
      end

      block_sizes = blocks.map { |block| block.code.length }
      total_bytes = block_sizes.sum
      str << "\n"
      str << "Total code size: #{total_bytes} bytes"
      str << "\n"

      str
    end

    def self.comments_for(start_address, end_address)
      Primitive.comments_for(start_address, end_address)
    end

    def self.graphviz_for(iseq)
      iseq = RubyVM::InstructionSequence.of(iseq)
      cs = Disasm.new

      highlight = ->(comment) { "<b>#{comment}</b>" }
      linebreak = "<br align=\"left\"/>\n"

      buff = +''
      blocks = blocks_for(iseq).sort_by(&:id)
      buff << "digraph g {\n"

      # Write the iseq info as a legend
      buff << "  legend [shape=record fontsize=\"30\" fillcolor=\"lightgrey\" style=\"filled\"];\n"
      buff << "  legend [label=\"{ Instruction Disassembly For: | {#{iseq.base_label}@#{iseq.absolute_path}:#{iseq.first_lineno}}}\"];\n"

      # Subgraph contains disassembly
      buff << "  subgraph disasm {\n"
      buff << "  node [shape=record fontname=\"courier\"];\n"
      buff << "  edge [fontname=\"courier\" penwidth=3];\n"
      blocks.each do |block|
        disasm = disasm_block(cs, block, highlight)

        # convert newlines to breaks that graphviz understands
        disasm.gsub!(/\n/, linebreak)

        # strip leading whitespace
        disasm.gsub!(/^\s+/, '')

        buff << "b#{block.id} [label=<#{disasm}>];\n"
        buff << block.outgoing_ids.map { |id|
          next_block = blocks.bsearch { |nb| id <=> nb.id }
          if next_block.address == (block.address + block.code.length)
            "b#{block.id} -> b#{id}[label=\"Fall\"];"
          else
            "b#{block.id} -> b#{id}[label=\"Jump\" style=dashed];"
          end
        }.join("\n")
        buff << "\n"
      end
      buff << "  }"
      buff << "}"
      buff
    end

    def self.disasm_block(cs, block, highlight)
      comments = comments_for(block.address, block.address + block.code.length)
      comment_idx = 0
      str = +''
      cs.disasm(block.code, block.address).each do |i|
        while (comment = comments[comment_idx]) && comment.address <= i.address
          str << "  ; #{highlight.call(comment.comment)}\n"
          comment_idx += 1
        end

        str << sprintf(
          "  %<address>08x:  %<instruction>s\t%<details>s\n",
          address: i.address,
          instruction: i.mnemonic,
          details: i.op_str
        )
      end
      str
    end
  end

  # Return a hash for statistics generated for the --yjit-stats command line option.
  # Return nil when option is not passed or unavailable.
  def self.runtime_stats
    # defined in yjit_iface.c
    Primitive.get_yjit_stats
  end

  # Discard statistics collected for --yjit-stats.
  def self.reset_stats!
    # defined in yjit_iface.c
    Primitive.reset_stats_bang
  end

  def self.stats_enabled?
    Primitive.yjit_stats_enabled_p
  end

  def self.enabled?
    Primitive.cexpr! 'rb_yjit_enabled_p() ? Qtrue : Qfalse'
  end

  # Avoid calling a method here to not interfere with compilation tests
  if Primitive.yjit_stats_enabled_p
    at_exit { _print_stats }
  end

  class << self
    private

    # Format and print out counters
    def _print_stats
      stats = runtime_stats
      return unless stats

      $stderr.puts("***YJIT: Printing YJIT statistics on exit***")

      print_counters(stats, prefix: 'send_', prompt: 'method call exit reasons: ')
      print_counters(stats, prefix: 'invokesuper_', prompt: 'invokesuper exit reasons: ')
      print_counters(stats, prefix: 'leave_', prompt: 'leave exit reasons: ')
      print_counters(stats, prefix: 'gbpp_', prompt: 'getblockparamproxy exit reasons: ')
      print_counters(stats, prefix: 'getivar_', prompt: 'getinstancevariable exit reasons:')
      print_counters(stats, prefix: 'setivar_', prompt: 'setinstancevariable exit reasons:')
      print_counters(stats, prefix: 'oaref_', prompt: 'opt_aref exit reasons: ')
      print_counters(stats, prefix: 'expandarray_', prompt: 'expandarray exit reasons: ')
      print_counters(stats, prefix: 'opt_getinlinecache_', prompt: 'opt_getinlinecache exit reasons: ')
      print_counters(stats, prefix: 'invalidate_', prompt: 'invalidation reasons: ')

      side_exits = total_exit_count(stats)
      total_exits = side_exits + stats[:leave_interp_return]

      # Number of instructions that finish executing in YJIT.
      # See :count-placement: about the subtraction.
      retired_in_yjit = stats[:exec_instruction] - side_exits

      # Average length of instruction sequences executed by YJIT
      avg_len_in_yjit = retired_in_yjit.to_f / total_exits

      # Proportion of instructions that retire in YJIT
      total_insns_count = retired_in_yjit + stats[:vm_insns_count]
      yjit_ratio_pct = 100.0 * retired_in_yjit.to_f / total_insns_count

      $stderr.puts "bindings_allocations:  " + ("%10d" % stats[:binding_allocations])
      $stderr.puts "bindings_set:          " + ("%10d" % stats[:binding_set])
      $stderr.puts "compiled_iseq_count:   " + ("%10d" % stats[:compiled_iseq_count])
      $stderr.puts "compiled_block_count:  " + ("%10d" % stats[:compiled_block_count])
      $stderr.puts "invalidation_count:    " + ("%10d" % stats[:invalidation_count])
      $stderr.puts "constant_state_bumps:  " + ("%10d" % stats[:constant_state_bumps])
      $stderr.puts "inline_code_size:      " + ("%10d" % stats[:inline_code_size])
      $stderr.puts "outlined_code_size:    " + ("%10d" % stats[:outlined_code_size])

      $stderr.puts "total_exit_count:      " + ("%10d" % total_exits)
      $stderr.puts "total_insns_count:     " + ("%10d" % total_insns_count)
      $stderr.puts "vm_insns_count:        " + ("%10d" % stats[:vm_insns_count])
      $stderr.puts "yjit_insns_count:      " + ("%10d" % stats[:exec_instruction])
      $stderr.puts "ratio_in_yjit:         " + ("%9.1f" % yjit_ratio_pct) + "%"
      $stderr.puts "avg_len_in_yjit:       " + ("%10.1f" % avg_len_in_yjit)

      print_sorted_exit_counts(stats, prefix: "exit_")
    end

    def print_sorted_exit_counts(stats, prefix:, how_many: 20, left_pad: 4)
      exits = []
      stats.each do |k, v|
        if k.start_with?(prefix)
          exits.push [k.to_s.delete_prefix(prefix), v]
        end
      end

      exits = exits.sort_by { |name, count| -count }[0...how_many]
      total_exits = total_exit_count(stats)

      top_n_total = exits.map { |name, count| count }.sum
      top_n_exit_pct = 100.0 * top_n_total / total_exits

      $stderr.puts "Top-#{how_many} most frequent exit ops (#{"%.1f" % top_n_exit_pct}% of exits):"

      longest_insn_name_len = exits.map { |name, count| name.length }.max
      exits.each do |name, count|
        padding = longest_insn_name_len + left_pad
        padded_name = "%#{padding}s" % name
        padded_count = "%10d" % count
        percent = 100.0 * count / total_exits
        formatted_percent = "%.1f" % percent
        $stderr.puts("#{padded_name}: #{padded_count} (#{formatted_percent}%)" )
      end
    end

    def total_exit_count(stats, prefix: "exit_")
      total = 0
      stats.each do |k,v|
        total += v if k.start_with?(prefix)
      end
      total
    end

    def print_counters(counters, prefix:, prompt:)
      $stderr.puts(prompt)
      counters = counters.filter { |key, _| key.start_with?(prefix) }
      counters.filter! { |_, value| value != 0 }
      counters.transform_keys! { |key| key.to_s.delete_prefix(prefix) }

      if counters.empty?
        $stderr.puts("    (all relevant counters are zero)")
        return
      end

      counters = counters.to_a
      counters.sort_by! { |(_, counter_value)| counter_value }
      longest_name_length = counters.max_by { |(name, _)| name.length }.first.length
      total = counters.sum { |(_, counter_value)| counter_value }

      counters.reverse_each do |(name, value)|
        percentage = value.fdiv(total) * 100
        $stderr.printf("    %*s %10d (%4.1f%%)\n", longest_name_length, name, value, percentage);
      end
    end
  end
end