Cached respond to

[tenderlove]

Use the pCMC for calls to respond_to?. This patch only works with "positive" cases (cases where respond_to? will return true).

This change makes the true case of respond to about 8x faster but the difference depends on the depth of the module:

[aaron@tc-lan-adapter ~/g/ruby (cached-respond-to)]$ make benchmark ITEM='respond_to'
/Users/aaron/.rubies/ruby-trunk/bin/ruby --disable=gems -rrubygems -I./benchmark/lib ./benchmark/benchmark-driver/exe/benchmark-driver \
	            --executables="compare-ruby::/Users/aaron/.rubies/ruby-trunk/bin/ruby --disable=gems -I.ext/common --disable-gem" \
	            --executables="built-ruby::./miniruby -I./lib -I. -I.ext/common  ./tool/runruby.rb --extout=.ext  -- --disable-gems --disable-gem" \
	            --output=markdown --output-compare $(find ./benchmark -maxdepth 1 -name 'respond_to' -o -name '*respond_to*.yml' -o -name '*respond_to*.rb' | sort) 
# Iteration per second (i/s)

|                  |compare-ruby|built-ruby|
|:-----------------|-----------:|---------:|
|respond_to_false  |      3.556M|    3.383M|
|                  |       1.05x|         -|
|respond_to_true   |      3.929M|   33.893M|
|                  |           -|     8.63x|

[ko1]

which case on this else path?

[tenderlove]

I'm not 100% sure. I haven't had time to investigate why we need this else case :(

[tenderlove]

I found the case for the else path. Ruby code like this:

module Foo
  module_function def omgomg; end
  instance_method(:omgomg) # called here
end

Here is the debugging info:

(lldb) bt
* thread #1, name = 'miniruby', stop reason = signal SIGABRT
  * frame #0: 0x00007ffff7c3818b libc.so.6`raise + 203
    frame #1: 0x00007ffff7c17859 libc.so.6`abort + 299
    frame #2: 0x0000555555642e19 miniruby`die at error.c:737:5
    frame #3: 0x0000555555642e0b miniruby`rb_bug(fmt="hello") at error.c:760:5
    frame #4: 0x00005555558b8894 miniruby`method_entry_resolve_refinement(klass=0x0000555555a7a940, id=30705, with_refinement=1, defined_class_ptr=0x00007fffffffb830) at vm_method.c:1131:9
    frame #5: 0x00005555558b85aa miniruby`rb_method_entry_with_refinements(klass=0x0000555555a7a940, id=30705, defined_class_ptr=0x00007fffffffb830) at vm_method.c:1156:12
    frame #6: 0x000055555577b09d miniruby`mnew(klass=0x0000555555a7a940, obj=0x0000000000000034, id=30705, mclass=0x0000555555ad2050, scope=0) at proc.c:1662:14
    frame #7: 0x0000555555778b5e miniruby`rb_mod_instance_method(mod=0x0000555555a7a940, vid=0x000000000077f10c) at proc.c:2068:12
    frame #8: 0x00005555558e6830 miniruby`ractor_safe_call_cfunc_1(recv=0x0000555555a7a940, argc=1, argv=0x00007ffff7808060, func=(miniruby`rb_mod_instance_method at proc.c:2063)) at vm_insnhelper.c:2645:12
    frame #9: 0x00005555558e1ae8 miniruby`vm_call_cfunc_with_frame(ec=0x0000555555a55520, reg_cfp=0x00007ffff7907f68, calling=0x00007fffffffbc40, cd=0x0000555555b76aa0) at vm_insnhelper.c:2821:11
    frame #10: 0x00005555558da43d miniruby`vm_call_cfunc(ec=0x0000555555a55520, reg_cfp=0x00007ffff7907f68, calling=0x00007fffffffbc40, cd=0x0000555555b76aa0) at vm_insnhelper.c:2842:12
    frame #11: 0x00005555558d9d17 miniruby`vm_call_method_each_type(ec=0x0000555555a55520, cfp=0x00007ffff7907f68, calling=0x00007fffffffbc40, cd=0x0000555555b76aa0) at vm_insnhelper.c:3324:16
    frame #12: 0x00005555558d9795 miniruby`vm_call_method(ec=0x0000555555a55520, cfp=0x00007ffff7907f68, calling=0x00007fffffffbc40, cd=0x0000555555b76aa0) at vm_insnhelper.c:3417:20
    frame #13: 0x00005555558bc35d miniruby`vm_call_general(ec=0x0000555555a55520, reg_cfp=0x00007ffff7907f68, calling=0x00007fffffffbc40, cd=0x0000555555b76aa0) at vm_insnhelper.c:3464:12
    frame #14: 0x00005555558d0b20 miniruby`vm_sendish(ec=0x0000555555a55520, reg_cfp=0x00007ffff7907f68, cd=0x0000555555b76aa0, block_handler=0x0000000000000000, method_explorer=(miniruby`vm_search_method_wrap at vm_insnhelper.c:4356)) at vm_insnhelper.c:4412:11
    frame #15: 0x00005555558a4126 miniruby`vm_exec_core(ec=0x0000555555a55520, initial=0x0000000000000000) at insns.def:789:11
    frame #16: 0x00005555558c633c miniruby`rb_vm_exec(ec=0x0000555555a55520, mjit_enable_p=1) at vm.c:2165:22
    frame #17: 0x00005555558c74a0 miniruby`rb_iseq_eval_main(iseq=0x0000555555a7ab20) at vm.c:2422:11
    frame #18: 0x000055555565093b miniruby`rb_ec_exec_node(ec=0x0000555555a55520, n=0x0000555555a7ab20) at eval.c:317:2
    frame #19: 0x0000555555650782 miniruby`ruby_run_node(n=0x0000555555a7ab20) at eval.c:375:30
    frame #20: 0x000055555557d358 miniruby`main(argc=2, argv=0x00007fffffffe518) at main.c:50:9
    frame #21: 0x00007ffff7c190b3 libc.so.6`__libc_start_main + 243
    frame #22: 0x000055555557d21e miniruby`_start + 46
(lldb) f 4
frame #4: 0x00005555558b8894 miniruby`method_entry_resolve_refinement(klass=0x0000555555a7a940, id=30705, with_refinement=1, defined_class_ptr=0x00007fffffffb830) at vm_method.c:1131:9
   1128	    if (RB_TYPE_P(klass, T_CLASS) || RB_TYPE_P(klass, T_ICLASS)) {
   1129	        me = (const rb_method_entry_t*)callable_method_entry(klass, id, defined_class_ptr);
   1130	    } else {
-> 1131	        rb_bug("hello");
   1132	        me = search_method_protect(klass, id, defined_class_ptr);
   1133	    }
   1134	
(lldb) command script import -r misc/lldb_cruby.py
lldb scripts for ruby has been installed.
(lldb) rp klass
bits [     ]
T_MODULE: (struct RClass) $1 = {
  basic = (flags = 0x0000000100000043, klass = 0x0000555555a7a8a0)
  super = 0x0000000000000000
  ptr = 0x0000555555b8de60
  class_serial = 577
}
(lldb) 

[tenderlove]

Is it safe to use the cme in place of the me? To fix respond_to? we just need to fix this location:

ruby/vm_method.c

Line 1359 in 383d3c3

me = method_entry_resolve_refinement(klass, id, TRUE, NULL);

@ko1 should I introduce a new method for use inside rb_method_boundp?

[ko1]

new method? new function?

[ko1]

cme is specialized version of me, so cme is me (me is sometimes cme, but sometimes not).

[ko1]

#3899 should be better

[tenderlove]

@ko1 thanks!