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Module: RubyVM::ZJIT

Relationships & Source Files
Defined in: zjit.rb

Overview

This module allows for introspection of ZJIT, 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 ZJIT does not support the particular platform for which CRuby is built.

Class Attribute Summary

Class Method Summary

Class Attribute Details

.enabled? ⇒ Boolean (readonly)

Check if ZJIT is enabled

[ GitHub ]

  
# File 'zjit.rb', line 24

def enabled?
  Primitive.cexpr! 'RBOOL(rb_zjit_enabled_p)'
end

.max_compile_time_ns (rw)

The maximum amount of time ZJIT is allowed to spend compiling. When .total_compile_time_ns goes over max_compile_time_ns, YJIT pause compilation until max_compile_time_ns is raised. If set to 0, there is no limit. This is a best-effort functionality, there are situations in which ZJIT may still compile even when paused. This feature is intended to be used to control how fast the JIT warms up, to spread the compilation overhead over a longer period of time.

[ GitHub ]

  
# File 'zjit.rb', line 78

def max_compile_time_ns
  Primitive.rb_zjit_max_compile_time_ns_get
end

.max_compile_time_ns=(max_compile_time_ns) (rw)

::Set the maximum amount of time YJIT is allowed to spend compiling.

[ GitHub ]

  
# File 'zjit.rb', line 83

def max_compile_time_ns=(max_compile_time_ns)
  Primitive.rb_zjit_max_compile_time_ns_set(max_compile_time_ns)
end

.stats_enabled? ⇒ Boolean (readonly)

Check if --zjit-stats is used

[ GitHub ]

  
# File 'zjit.rb', line 88

def stats_enabled?
  Primitive.rb_zjit_stats_enabled_p
end

.trace_exit_locations_enabled? ⇒ Boolean (readonly)

Check if --zjit-trace-exits is used

[ GitHub ]

  
# File 'zjit.rb', line 41

def trace_exit_locations_enabled?
  Primitive.rb_zjit_trace_exit_locations_enabled_p
end

Class Method Details

.add_jit_hook(hook) (private)

This method is for internal use only.

Register a block to be called when ZJIT is enabled

[ GitHub ]

  
# File 'zjit.rb', line 238

def add_jit_hook(hook)
  @jit_hooks << hook
end

.assert_compiles

This method is for internal use only.

Assert that any future ZJIT compilation will return a function pointer

[ GitHub ]

  
# File 'zjit.rb', line 230

def assert_compiles # :nodoc:
  Primitive.rb_zjit_assert_compiles
end

.call_jit_hooks (private)

This method is for internal use only.

Run ZJIT hooks registered by #with_jit

[ GitHub ]

  
# File 'zjit.rb', line 243

def call_jit_hooks
  @jit_hooks.each(&:call)
  @jit_hooks.clear
end

.enable

Enable ZJIT compilation.

[ GitHub ]

  
# File 'zjit.rb', line 29

def enable
  return false if enabled?

  if Primitive.cexpr! 'RBOOL(rb_yjit_enabled_p)'
    warn("Only one JIT can be enabled at the same time.")
    return false
  end

  Primitive.rb_zjit_enable
end

.induce_breakpoint!

A directive for the compiler to emit a breakpoint instruction at the call site of this method. To show this to ZJIT, say .induce_breakpoint! verbatim. Other forms are too dynamic to detect during compilation.

[ GitHub ]

  
# File 'zjit.rb', line 62

def induce_breakpoint! = nil

.induce_compile_failure!

A directive for the compiler to fail to compile the call to this method. To show this to ZJIT, say .induce_compile_failure! verbatim. Other forms are too dynamic to detect during compilation.

Actually running this method does nothing, whether ZJIT sees the call or not.

[ GitHub ]

  
# File 'zjit.rb', line 50

def induce_compile_failure! = nil

.induce_side_exit!

A directive for the compiler to exit out of compiled code at the call site of this method. To show this to ZJIT, say .induce_side_exit! verbatim. Other forms are too dynamic to detect during compilation.

Actually running this method does nothing, whether ZJIT sees the call or not.

[ GitHub ]

  
# File 'zjit.rb', line 57

def induce_side_exit! = nil

.number_with_delimiter(number) (private)

This method is for internal use only.
[ GitHub ]

  
# File 'zjit.rb', line 303

def number_with_delimiter(number)
  s = number.to_s
  i = s.index('.') || s.size
  s.insert(i -= 3, ',') while i > 3
  s
end

.reset_stats!

Discard statistics collected for --zjit-stats.

[ GitHub ]

  
# File 'zjit.rb', line 98

def reset_stats!
  Primitive.rb_zjit_reset_stats_bang
end

.stats(target_key = nil)

Return ZJIT statistics as a ::Hash

[ GitHub ]

  
# File 'zjit.rb', line 93

def stats(target_key = nil)
  Primitive.rb_zjit_stats(target_key)
end

.stats_string

Get the summary of ZJIT statistics as a ::String

[ GitHub ]

  
# File 'zjit.rb', line 103

def stats_string
  return unless stats = self.stats
  buf = +"***ZJIT: Printing ZJIT statistics on exit***\n"

  if stats[:guard_type_count]&.nonzero?
    stats[:guard_type_exit_ratio] = stats[:exit_guard_type_failure].to_f / stats[:guard_type_count] * 100
  end
  if stats[:guard_shape_count]&.nonzero?
    stats[:guard_shape_exit_ratio] = stats[:exit_guard_shape_failure].to_f / stats[:guard_shape_count] * 100
  end
  if stats[:code_region_bytes]&.nonzero?
    stats[:side_exit_size_ratio] = stats[:side_exit_size_bytes].to_f / stats[:code_region_bytes] * 100
  end
  if stats[:compile_time_ns]&.nonzero?
    stats[:compile_side_exit_time_ratio] = stats[:compile_side_exit_time_ns].to_f / stats[:compile_time_ns] * 100
  end

  # Show counters independent from exit_* or dynamic_send_*
  print_counters_with_prefix(prefix: 'not_inlined_cfuncs_', prompt: 'not inlined C methods', buf:, stats:, limit: 20)
  print_counters_with_prefix(prefix: 'ccall_', prompt: 'calls to C functions from JIT code', buf:, stats:, limit: 20)
  print_counters_with_prefix(prefix: 'iseq_calls_count_', prompt: 'most called JIT functions', buf:, stats:, limit: 20)
  # Don't show not_annotated_cfuncs right now because it mostly duplicates not_inlined_cfuncs
  # print_counters_with_prefix(prefix: 'not_annotated_cfuncs_', prompt: 'not annotated C methods', buf:, stats:, limit: 20)

  # Show fallback counters, ordered by the typical amount of fallbacks for the prefix at the time
  print_counters_with_prefix(prefix: 'unspecialized_send_def_type_', prompt: 'not optimized method types for send', buf:, stats:, limit: 20)
  print_counters_with_prefix(prefix: 'unspecialized_super_def_type_', prompt: 'not optimized method types for super', buf:, stats:, limit: 20)
  print_counters_with_prefix(prefix: 'uncategorized_fallback_yarv_insn_', prompt: 'instructions with uncategorized fallback reason', buf:, stats:, limit: 20)
  print_counters_with_prefix(prefix: 'send_fallback_', prompt: 'send fallback reasons', buf:, stats:, limit: 20)
  print_counters_with_prefix(prefix: 'send_direct_fallback_context_', prompt: 'SendDirect fallback contexts', buf:, stats:, limit: 10)
  print_counters_with_prefix(prefix: 'setivar_fallback_', prompt: 'setivar fallback reasons', buf:, stats:, limit: 5)
  print_counters_with_prefix(prefix: 'getivar_fallback_', prompt: 'getivar fallback reasons', buf:, stats:, limit: 5)
  print_counters_with_prefix(prefix: 'definedivar_fallback_', prompt: 'definedivar fallback reasons', buf:, stats:, limit: 5)
  print_counters_with_prefix(prefix: 'invokeblock_handler_', prompt: 'invokeblock handler', buf:, stats:, limit: 10)
  print_counters_with_prefix(prefix: 'inline_reject_', prompt: 'HIR-level inlining rejection reasons', buf:, stats:, limit: 10)

  # Show most popular unsupported call features. Because each call can
  # use multiple complex features, a decrease in this number does not
  # necessarily mean an increase in number of optimized calls.
  print_counters_with_prefix(prefix: 'complex_arg_pass_', prompt: 'popular complex argument-parameter features not optimized', buf:, stats:, limit: 10)
  print_counters_with_prefix(prefix: 'caller_splat_profile_', prompt: 'caller splat length profiles', buf:, stats:, limit: 10)

  # Show exit counters, ordered by the typical amount of exits for the prefix at the time
  print_counters_with_prefix(prefix: 'compile_error_', prompt: 'compile error reasons', buf:, stats:, limit: 20)
  print_counters_with_prefix(prefix: 'unhandled_yarv_insn_', prompt: 'unhandled YARV insns', buf:, stats:, limit: 20)
  print_counters_with_prefix(prefix: 'unhandled_hir_insn_', prompt: 'unhandled HIR insns', buf:, stats:, limit: 20)
  print_counters_with_prefix(prefix: 'exit_', prompt: 'side exit reasons', buf:, stats:, limit: 20)

  # Show no-prefix counters, having the most important stat `ratio_in_zjit` at the end
  print_counters([
    :send_count,
    :dynamic_send_count,
    :optimized_send_count,
    :iseq_optimized_send_count,
    :inline_cfunc_optimized_send_count,
    :inline_iseq_optimized_send_count,
    :inline_method_count,
    :empty_inline_frame_count,
    :non_variadic_cfunc_optimized_send_count,
    :variadic_cfunc_optimized_send_count,
    :caller_splat_optimized,
  ], buf:, stats:, right_align: true, base: :send_count)
  print_counters([
    :dynamic_setivar_count,
    :dynamic_getivar_count,
    :dynamic_definedivar_count,

    :compiled_iseq_count,
    :compiled_side_exit_count,
    :failed_iseq_count,

    :compile_time_ns,
    :compile_side_exit_time_ns,
    :compile_side_exit_time_ratio,
    :compile_hir_time_ns,
    :compile_hir_build_time_ns,
    :compile_hir_strength_reduce_time_ns,
    :compile_hir_inline_methods_time_ns,
    :compile_hir_remove_trivial_block_params_time_ns,
    :compile_hir_optimize_load_store_time_ns,
    :compile_hir_canonicalize_time_ns,
    :compile_hir_fold_constants_time_ns,
    :compile_hir_clean_cfg_time_ns,
    :compile_hir_remove_redundant_patch_points_time_ns,
    :compile_hir_remove_duplicate_check_interrupts_time_ns,
    :compile_hir_eliminate_dead_code_time_ns,
    :compile_lir_time_ns,
    :profile_time_ns,
    :gc_time_ns,
    :invalidation_time_ns,

    :vm_write_jit_frame_count,
    :vm_write_sp_count,
    :vm_write_locals_count,
    :vm_write_stack_count,
    :vm_write_to_parent_iseq_local_count,

    :guard_type_count,
    :guard_type_exit_ratio,
    :guard_shape_count,
    :guard_shape_exit_ratio,

    :load_field_count,
    :store_field_count,

    :throw_count,

    :side_exit_size_bytes,
    :side_exit_size_ratio,
    :jit_frame_heap_bytes,
    :jit_frame_region_bytes,
    :code_region_bytes,
    :zjit_alloc_bytes,
    :total_mem_bytes,
    :total_native_stack_bytes,

    :side_exit_count,
    :total_insn_count,
    :vm_insn_count,
    :zjit_insn_count,
    :ratio_in_zjit,
  ], buf:, stats:)

  buf
end

.total_compile_time_ns

Monotonically increasing counter representing the amount of wall time nanoseconds spent compiling.

[ GitHub ]

  
# File 'zjit.rb', line 66

def total_compile_time_ns
  Primitive.rb_zjit_total_compile_time_ns_get
end