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![remove local variable's names
• make bytecode without irep->lv
static void
irep_remove_lv(mrb_state *mrb, mrb_irep *irep)
{
int i;
if (irep->lv) {
mrb_free(mrb, irep->lv);
irep->lv = NULL;
}
for (i = 0; i < irep->rlen; ++i) {
irep_remove_lv(mrb, irep->reps[i]);
}
}](https://image.slidesharecdn.com/rubykaigi2018-yamanekko-180618145908/75/mruby-can-be-more-lightweight-26-2048.jpg)
Uploaded byyamanekko
mruby can be more lightweight
mruby can be made more lightweight by reducing its memory usage. Techniques include assigning symbols and method definitions to read-only memory (ROM) instead of random-access memory (RAM), using arrays instead of hash tables to store method lookup data, removing local variable name metadata from bytecode, and tuning configuration options like hash table size. This allows mruby to run on microcontrollers with very limited RAM and ROM, expanding its usage in small low-cost embedded devices.
mruby can be more lightweight
- 1. mruby can bemore lightweight 2018-06-01 RubyKaigi 2018 Yurie Yamane Team Yamanekko
- 2. About me • yurieyamane • Team yamanekko • GitHub: https://github.com/yamanekko • Qiita: https://qiita.com/yamanekko • a member of Toppers project • a staff of SWEST (Summer Workshop on Embedded System Technologies) https://swest.toppers.jp/ TOPAME matz
- 3. About me • smallermruby • low cost microcomputer • IDE for mruby(VS Code) • porting nomitory to VS Code • DEMO • mruby for ET robot contest sponsors wanted!
- 4. Today's topic • howto make mruby smaller • why? • how?
- 5.
- 6. price RAM ROMmruby LEGO MindStorms 60,000yen 64MB 16MB OK GR-PEACH 10,000yen 10MB 8MB OK nucleo F412ZG 3,000yen 256KB 1024KB OK nucleo F411RE 2,000yen 128KB 512KB OK Arduino uno 3,000yen 2KB 32KB NG porting microcomputers ref)
- 7. F411RE or F401RE F411REF401RE RAM:96KB ROM:512KB RAM:128KB ROM:512KB
- 8.
- 9. how to reduce A B C reduceRAM use ROM tuning by #define change implementation
- 10. RAM size 0 40000 80000 120000 160000 default AB and C 66919 82783 152829
- 11.
- 12.
- 13. • why methoddefinition in RAM?
- 14. RAM Assigned symbols toROM predefined method RAM ROM predefined method method method
- 15. RAM Assigned symbols toROM symbol symbol RAM ROM predefined method method symbol symbol predefined method method
- 16. RAM RAM ROM Assigned symbols toROM khash method khash method method
- 17. method table struct RClass{ MRB_OBJECT_HEADER; struct iv_tbl *iv; struct kh_mt *mt; struct RClass *super; }; RClass
- 18. RAM method table keys vals typedef structkh_mt{ khint_t n_buckets; khint_t size; khint_t n_occupied; uint8_t *ed_flags; mrb_sym *keys; mrb_method_t *vals; } kh_mt_t; ed_flags buckets https://tatsu-zine.com/books/ruby-under-a-microscope-ja "Ruby Under a Microscope"
- 19. method table RClass mt2 struct RClass{ MRB_OBJECT_HEADER; struct iv_tbl *iv; struct kh_mt *mt; #ifdef USE_PRESYM struct method_table *mt2; #endif struct RClass *super; };
- 20. hash vs array keys vals Array RAM ROMstruct method_table{ mrb_sym sym; mrb_method_t method; }; typedef struct kh_mt{ khint_t n_buckets; khint_t size; khint_t n_occupied; uint8_t *ed_flags; mrb_sym *keys; mrb_method_t *vals; } kh_mt_t; ed_flags buckets sym method
- 21. Ruby method toC function • Ex.String class String class to_i mrb_str_to_i upcase mrb_str_upcase length mrb_str_size reverse mrb_str_reverse size mrb_str_size mrb_define_method(mrb, a, "size",mrb_str_size, MRB_ARGS_NONE());
- 22. Ruby method toC function • perf method name id to_i 290 upcase 298 length 212 reverse 259 size 271 id function name 290 mrb_str_to_i 298 mrb_str_upcase 212 mrb_str_size 259 mrb_str_reverse 271 mrb_str_size
- 23. extract symbols • *.c •intern literal • method • const • global const • class • module • class method • *.rb • def • class mrb_intern_lit(mrb, "to_a") mrb_define_class(mrb, "Array", mrb->object_class); mrb_define_method(mrb, a, "+", mrb_ary_plus, MRB_ARGS_REQ(1)); mrb_define_method(mrb, a, "size",mrb_ary_size, MRB_ARGS_NONE()); class Foo def foo (...) end end
- 24. ROM mrb_method_search_vm Dynamically added methods aredefined here method RAM khash method
- 25.
- 26. remove local variable'snames • make bytecode without irep->lv static void irep_remove_lv(mrb_state *mrb, mrb_irep *irep) { int i; if (irep->lv) { mrb_free(mrb, irep->lv); irep->lv = NULL; } for (i = 0; i < irep->rlen; ++i) { irep_remove_lv(mrb, irep->reps[i]); } }
- 27. khash size • KHASH_DEFAULT_SIZE4 • KHASH_MIN_SIZE #ifndef KHASH_DEFAULT_SIZE # define KHASH_DEFAULT_SIZE 32 #endif #define KHASH_MIN_SIZE 8 # define KHASH_DEFAULT_SIZE 4 #ifndef KHASH_DEFAULT_SIZE # define KHASH_DEFAULT_SIZE 32 #endif #define KHASH_MIN_SIZE 4
- 28.
- 29. delete -g option •mrbc.compile_options = "-g -B%{funcname} -o-"
- 30. • MRB_USE_ETEXT_EDATA mrbconf.md . =ALIGN(4); _etext = .; /* define a global symbols at end of code */ } >FLASH { . = ALIGN(4); _sdata = .; /* create a global symbol at data start */ *(.data) /* .data sections */ *(.data*) /* .data* sections */ . = ALIGN(4); _edata = .; /* define a global symbol at data end */ } >RAM AT> FLASH
- 31. • MRB_HEAP_PAGE_SIZE • Specifiesnumber of `RBasic` per each heap page. • MRB_WORD_BOXING • If defined represent `mrb_value` as a word. • If defined `Float` will be a mruby object with `RBasic`. • MRB_STR_BUF_MIN_SIZE • Specifies initial capacity of `RString` created by `mrb_str_buf_new` function. mrbconf.md
- 32.
- 33. RClass mt2 to iv RClass structRClass { MRB_OBJECT_HEADER; struct iv_tbl *iv; struct kh_mt *mt; #ifdef USE_PRESYM struct method_table *mt2; #endif struct RClass *super; }; iv mt2 iv mt2
- 34. • Implementation tounsupported class • known bug • "remove_method" can't remove method on ROM 🙀
- 35.