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.
# File tmp/rubies/ruby-3.4.0-preview1/yjit.rb, line 238
def self.code_gc
Primitive.rb_yjit_code_gc
end
Discard existing compiled code to reclaim memory and allow for recompilations in the future.
# File tmp/rubies/ruby-3.4.0-preview1/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
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 tmp/rubies/ruby-3.4.0-preview1/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
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 tmp/rubies/ruby-3.4.0-preview1/yjit.rb, line 12
def self.enabled?
Primitive.cexpr! 'RBOOL(rb_yjit_enabled_p)'
end
Check if YJIT is enabled.
# File tmp/rubies/ruby-3.4.0-preview1/yjit.rb, line 27
def self.reset_stats!
Primitive.rb_yjit_reset_stats_bang
end
Discard statistics collected for --yjit-stats.
# File tmp/rubies/ruby-3.4.0-preview1/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
Return a hash for statistics generated for the --yjit-stats command line option. Return nil when option is not passed or unavailable.
# File tmp/rubies/ruby-3.4.0-preview1/yjit.rb, line 17
def self.stats_enabled?
Primitive.rb_yjit_stats_enabled_p
end
Check if --yjit-stats is used.
# File tmp/rubies/ruby-3.4.0-preview1/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
Format and print out counters as a String. This returns a non-empty content only when --yjit-stats is enabled.