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![Issues
1. we need to clear
rb_control_frame_t::block_iseq for
every frame setup. It consumes space (a
VALUE for each frame) and initializing
time.
2. There are several block passing ways by
ISeq (iter{...}), Proc(iter(&pr)),
Symbol(iter(:sym)). However, they are
not optimized (for Symbol blocks, there
is only ad-hoc check code).
3. Env (and Proc, Binding) objects are not
WB-protected ([Bug #10212]).
Method dispatch (etc)
improvements
Cleanup src code
Improve GC perf.](https://image.slidesharecdn.com/2017oedo06-170322020641/75/Ruby-2-4-Internals-19-2048.jpg)
![Idea
Lightweight escape detection
•Move cfp->flags to ep[0]
•Introduce a VM_ENV_FLAG_ESCAPED flag to
represent escaped Env.
• // Before
#define VM_EP_IN_HEAP_P(th, ep) (!((th)->stack <= (ep) && (ep) < ((th)->stack + (th)->stack_size)))
• // After
#define VM_EP_IN_HEAP_P(ep) (ep[0] & VM_ENV_FLAG_ESCAPED)](https://image.slidesharecdn.com/2017oedo06-170322020641/75/Ruby-2-4-Internals-27-2048.jpg)
![Final code
vm_env_write(const VALUE *ep, int index, VALUE v) {
VALUE flags = ep[VM_ENV_DATA_INDEX_FLAGS];
if (LIKELY((flags & VM_ENV_FLAG_WB_REQUIRED) == 0)) {
*(ep - idx) = val; /* mostly used */
}
else {
/* remember env value forcibly */
vm_env_write_slowpath(ep, index, v);
}
}](https://image.slidesharecdn.com/2017oedo06-170322020641/75/Ruby-2-4-Internals-30-2048.jpg)
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Ruby 2.4 Internals
- 1.
- 4. Note: Ruby 2.4.0 has severalbugs. Note2: No x.y.0 doesn’t have several bugs.
- 5.
- 6. New features written ina release announcement • Introduce hash table improvement (by Vladimir Makarov) • Binding#irb: Start a REPL session similar to binding.pry • Unify Fixnum and Bignum into Integer • String supports Unicode case mappings • Performance improvements • Array#max, Array#min • Regexp#match? • speed up instance variable access • Debugging • Thread#report_on_exception and Thread.report_on_exception • Thread deadlock detection now shows threads with their backtrace and dependency • Other notable changes since 2.3 • Support OpenSSL 1.1.0 (drop support for 0.9.7 or prior) • ext/tk is now removed from stdlib Feature #8539 • XMLRPC is now removed from stdlib Feature #12160
- 7.
- 8.
- 9.
- 13.
- 15. Bug #10212 MRIis not for lambda calculus JRuby 26 sec mruby 27 sec MRI 114 sec
- 17.
- 18. Ruby 2.4 Internals Changeblock/env structs Koichi Sasada [email protected]
- 19. Issues 1. we needto clear rb_control_frame_t::block_iseq for every frame setup. It consumes space (a VALUE for each frame) and initializing time. 2. There are several block passing ways by ISeq (iter{...}), Proc(iter(&pr)), Symbol(iter(:sym)). However, they are not optimized (for Symbol blocks, there is only ad-hoc check code). 3. Env (and Proc, Binding) objects are not WB-protected ([Bug #10212]). Method dispatch (etc) improvements Cleanup src code Improve GC perf.
- 20. Patch •https://github.com/ruby/ruby/compare/tru nk...ko1:block_code •“Showing with 1,863additions and 1,070 deletions.”
- 21. Approaches •For (1), (2) •IntroduceBlock Handler (BH) •Using BH •For (3) •Introduce Write Barriers (WB) for Env objects
- 22. WB protected orunprotected? •Ruby 2.1.0 introduced Generational GC •Only newer objects •GenGC requires “Write barriers” (WB), but MRI allows WB unprotected objects (See my past presentations for details) •WB protected objects: GenGC → Fast •WB unprotected objects: Not GenGC → Slow
- 23. RubyVM::Env objects •Env objectsrepresent captured local variables •Each Proc or Binding has at least one Env object •Proc object “$pr” consists of 3 Env objects a = 1 1.times{|b| 1.times{|c| $pr = Proc.new{ # you can access a, b, c } } } Proc $pr Env c=0 Env b=0 Env a=1
- 24. RubyVM::Env objects were WB-unprotected •Theywere WB unprotected because: •Difficulty of implementation •Performance issue
- 25. Performance issue Assignment performance •Ruby 2.3 or before *(ep - idx) = val; • Naïve implementation #define VM_EP_IN_HEAP_P(th, ep) ¥ (!((th)->stack <= (ep) && ¥ (ep) < ((th)->stack + (th)->stack_size))) if (VM_EP_IN_HEAP_P(ep)) { RB_OBJ_WRITE(VM_ENV_EP_ENVVAL(ep), ep-idx, val); } else *(ep - idx) = val;
- 26. Ideas 1. Lightweight escapedetection 2. Skip WB except really required timing
- 27. Idea Lightweight escape detection •Movecfp->flags to ep[0] •Introduce a VM_ENV_FLAG_ESCAPED flag to represent escaped Env. • // Before #define VM_EP_IN_HEAP_P(th, ep) (!((th)->stack <= (ep) && (ep) < ((th)->stack + (th)->stack_size))) • // After #define VM_EP_IN_HEAP_P(ep) (ep[0] & VM_ENV_FLAG_ESCAPED)
- 28. Idea Skip WB exceptreally required timing 1. At initializing Env objects, VM_ENV_FLAG_WB_REQUIRED is true. 2. At first local variable assignment, VM_ENV_FLAG_WB_REQUIRED is true, we remember this Env object forcibly. And turn off this flag. 3. At next local variable assignment, VM_ENV_FLAG_WB_REQUIRED is false, so we can ignore WB protection. 4. At GC marking for this Env object, we turn on VM_ENV_FLAG_WB_REQUIRED and goto (2). Very danger technique because it depends on GC implementation
- 29. Naïve code #define VM_EP_IN_HEAP_P(th,ep) (!((th)->stack <= (ep) && (ep) < ((th)->stack + (th)->stack_size))) vm_env_write(const VALUE *ep, int index, VALUE v) { if (VM_EP_IN_HEAP_P(ep)) { RB_OBJ_WRITE(VM_ENV_EP_ENVVAL(ep), ep-idx, val); } else { *(ep - idx) = val; } }
- 30. Final code vm_env_write(const VALUE*ep, int index, VALUE v) { VALUE flags = ep[VM_ENV_DATA_INDEX_FLAGS]; if (LIKELY((flags & VM_ENV_FLAG_WB_REQUIRED) == 0)) { *(ep - idx) = val; /* mostly used */ } else { /* remember env value forcibly */ vm_env_write_slowpath(ep, index, v); } }
- 31.
- 32. Bug #10212 MRIis not for lambda calculus lc_fizzbuzz with MRI versions 0 50 100 150 ruby_2_0 ruby_2_1 ruby_2_2 ruby_2_3 trunk Executiontime(sec) app_lc_fizzbuzz
- 33. Bug #10212 MRIis not for lambda calculus lc_fizzbuzz with MRI, JRuby, mruby 36.976 18.706 40.185 0 10 20 30 40 50 trunk jruby mruby Executiontime(sec) app_lc_fizzbuzz
- 34. Summary •Ruby 2.4.0 hasmany improvements •Now Proc (Env) objects are WB protected and we have more faster GC (marking) •My ideas allow to protect Env objects without big performance impact
- 35. Thank you foryour attention Koichi Sasada <[email protected]>