summaryrefslogtreecommitdiff
path: root/yjit.rb
blob: 7c5311d79a8b20601145ca709120a0278cc266ab (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
# frozen_string_literal: true

# This module allows for introspection of YJIT, CRuby's experimental in-process
# just-in-time compiler. This module exists only to help develop YJIT, as such,
# everything in the module is highly implementation specific and comes with no
# API stability guarantee whatsoever.
#
# This module may not exist if YJIT does not support the particular platform
# for which CRuby is built. There is also no API stability guarantee as to in
# what situations this module is defined.
module RubyVM::YJIT
  # Check if YJIT is enabled
  def self.enabled?
    Primitive.cexpr! 'RBOOL(rb_yjit_enabled_p())'
  end

  def self.stats_enabled?
    Primitive.rb_yjit_stats_enabled_p
  end

  # Discard statistics collected for --yjit-stats.
  def self.reset_stats!
    Primitive.rb_yjit_reset_stats_bang
  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
    Primitive.rb_yjit_get_stats
  end

  # Produce disassembly for an iseq
  def self.disasm(iseq)
    # If a method or proc is passed in, get its iseq
    iseq = RubyVM::InstructionSequence.of(iseq)

    if self.enabled?
      # Produce the disassembly string
      # Include the YARV iseq disasm in the string for additional context
      iseq.disasm + "\n" + Primitive.rb_yjit_disasm_iseq(iseq)
    else
      iseq.disasm
    end
  end

  # Produce a list of instructions compiled by YJIT for an iseq
  def self.insns_compiled(iseq)
    # If a method or proc is passed in, get its iseq
    iseq = RubyVM::InstructionSequence.of(iseq)

    if self.enabled?
      Primitive.rb_yjit_insns_compiled(iseq)
    else
      Qnil
    end
  end

  def self.simulate_oom!
    Primitive.rb_yjit_simulate_oom_bang
  end

  # Avoid calling a method here to not interfere with compilation tests
  if Primitive.rb_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

      # Number of failed compiler invocations
      compilation_failure = stats[:compilation_failure]

      $stderr.puts "bindings_allocations:  " + ("%10d" % stats[:binding_allocations])
      $stderr.puts "bindings_set:          " + ("%10d" % stats[:binding_set])
      $stderr.puts "compilation_failure:   " + ("%10d" % compilation_failure) if compilation_failure != 0
      $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