module RubyVM::YJIT
This module allows for introspection of YJIT, CRuby’s just-in-time compiler. Everything in the module is highly implementation specific and the API might be less stable compared to the standard library.
This module may not exist if YJIT does not support the particular platform for which CRuby is built.
Public Class Methods
Discard existing compiled code to reclaim memory and allow for recompilations in the future.
# File ruby_3_3_5/yjit.rb, line 224 def self.code_gc Primitive.rb_yjit_code_gc end
Marshal
dumps exit locations to the given filename.
Usage:
If --yjit-exit-locations
is passed, a file named “yjit_exit_locations.dump” will automatically be generated.
If you want to collect traces manually, call dump_exit_locations
directly.
Note that calling this in a script will generate stats after the dump is created, so the stats data may include exits from the dump itself.
In a script call:
at_exit do RubyVM::YJIT.dump_exit_locations("my_file.dump") end
Then run the file with the following options:
ruby --yjit --yjit-trace-exits test.rb
Once the code is done running, use Stackprof to read the dump file. See Stackprof documentation for options.
# File ruby_3_3_5/yjit.rb, line 148 def self.dump_exit_locations(filename) unless trace_exit_locations_enabled? raise ArgumentError, "--yjit-trace-exits must be enabled to use dump_exit_locations." end File.binwrite(filename, Marshal.dump(RubyVM::YJIT.exit_locations)) end
Enable YJIT compilation. stats
option decides whether to enable YJIT stats or not.
-
false
: Disable stats. -
true
: Enable stats. Print stats at exit. -
:quiet
: Enable stats. Do not print stats at exit.
# File ruby_3_3_5/yjit.rb, line 36 def self.enable(stats: false) return false if enabled? at_exit { print_and_dump_stats } if stats Primitive.rb_yjit_enable(stats, stats != :quiet) end
Check if YJIT is enabled.
# File ruby_3_3_5/yjit.rb, line 12 def self.enabled? Primitive.cexpr! 'RBOOL(rb_yjit_enabled_p)' end
Discard statistics collected for --yjit-stats
.
# File ruby_3_3_5/yjit.rb, line 27 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.
# File ruby_3_3_5/yjit.rb, line 158 def self.runtime_stats(context: false) stats = Primitive.rb_yjit_get_stats(context) return stats if stats.nil? stats[:object_shape_count] = Primitive.object_shape_count return stats unless Primitive.rb_yjit_stats_enabled_p 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[:yjit_insns_count] - side_exits # Average length of instruction sequences executed by YJIT avg_len_in_yjit = total_exits > 0 ? retired_in_yjit.to_f / total_exits : 0 # 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 stats[:total_insns_count] = total_insns_count stats[:ratio_in_yjit] = yjit_ratio_pct # Make those stats available in RubyVM::YJIT.runtime_stats as well stats[:side_exit_count] = side_exits stats[:total_exit_count] = total_exits stats[:avg_len_in_yjit] = avg_len_in_yjit stats end
Check if --yjit-stats
is used.
# File ruby_3_3_5/yjit.rb, line 17 def self.stats_enabled? Primitive.rb_yjit_stats_enabled_p end
Format and print out counters as a String
. This returns a non-empty content only when --yjit-stats
is enabled.
# File ruby_3_3_5/yjit.rb, line 191 def self.stats_string # Lazily require StringIO to avoid breaking miniruby require 'stringio' strio = StringIO.new _print_stats(out: strio) strio.string end
Private Class Methods
Format large numbers with comma separators for readability
# File ruby_3_3_5/yjit.rb, line 480 def format_number(pad, number) s = number.to_s i = s.index('.') || s.size s.insert(i -= 3, ',') while i > 3 s.rjust(pad, ' ') end
Format a number along with a percentage over a total value
# File ruby_3_3_5/yjit.rb, line 488 def format_number_pct(pad, number, total) padded_count = format_number(pad, number) percentage = number.fdiv(total) * 100 formatted_pct = "%4.1f%%" % percentage "#{padded_count} (#{formatted_pct})" end
Print stats and dump exit locations
# File ruby_3_3_5/yjit.rb, line 241 def print_and_dump_stats if Primitive.rb_yjit_print_stats_p _print_stats end _dump_locations end