Hanneli (a.k.a @hannelita) é uma desenvolvedora fissurada por programar, aprender novas linguagens, frameworks, explodir capacitores, programar em C pra relaxar e comitar código útil (ou não) em projetos Open Source aleatórios que encontra vasculhando Githubs alheios. Ela também gosta de café, especialmente os do Starbucks. Neste 7Masters Ruby, ela apresentou a talk "Ruby performance distilled".

1. Ruby performance
distilled

2. Hi! I’m Hanneli

3. No advanced stuff
Fast snippets
You can agree or not

4. Why speed?
( ͡° ͜ʖ ͡°) ( ͡° ͜ʖ ͡°) ( ͡° ͜ʖ ͡°) ( ͡° ͜ʖ ͡°) ( ͡° ͜ʖ ͡°) ( ͡° ͜ʖ ͡°) ( ͡°
͜ʖ ͡°) ( ͡° ͜ʖ ͡°) ( ͡° ͜ʖ ͡°) ( ͡° ͜ʖ ͡°) ( ͡° ͜ʖ ͡°) ( ͡° ͜ʖ ͡°) ( ͡° ͜ʖ ͡°) (
͡° ͜ʖ ͡°) ( ͡° ͜ʖ ͡°) ( ͡° ͜ʖ ͡°) ( ͡° ͜ʖ ͡°) ( ͡° ͜ʖ ͡°) ( ͡° ͜ʖ ͡°) ( ͡° ͜ʖ ͡°)
( ͡° ͜ʖ ͡°) ( ͡° ͜ʖ ͡°) ( ͡° ͜ʖ ͡°) ( ͡° ͜ʖ ͡°) ( ͡° ͜ʖ ͡°)

5. Optimize makes my code
uglier
( ͡° ͜ʖ ͡°) ( ͡° ͜ʖ ͡°) ( ͡° ͜ʖ ͡°) ( ͡° ͜ʖ ͡°) ( ͡° ͜ʖ ͡°) ( ͡° ͜ʖ ͡°) ( ͡°
͜ʖ ͡°) ( ͡° ͜ʖ ͡°) ( ͡° ͜ʖ ͡°) ( ͡° ͜ʖ ͡°) ( ͡° ͜ʖ ͡°) ( ͡° ͜ʖ ͡°) ( ͡° ͜ʖ ͡°) (
͡° ͜ʖ ͡°) ( ͡° ͜ʖ ͡°) ( ͡° ͜ʖ ͡°) ( ͡° ͜ʖ ͡°) ( ͡° ͜ʖ ͡°) ( ͡° ͜ʖ ͡°) ( ͡° ͜ʖ ͡°)
( ͡° ͜ʖ ͡°) ( ͡° ͜ʖ ͡°) ( ͡° ͜ʖ ͡°) ( ͡° ͜ʖ ͡°) ( ͡° ͜ʖ ͡°)

6. Optimize makes my code
uglier

7. IoT
128GB RAM at Amazon 1GB RAM at Raspberry

8. There are several layers to
optimise
Source code optimisation
{
Search time
Sorting time
Complexity
Data Structures

9. Example #1 - counting
Loops are very common for Hardware
(1…65536).map { |i| i.to_s } (1…65536).map { &:to_s }

10. Example #2 - merge
Hashes happen a lot in Hardware
merge! merge

11. Example #3 - sub/gsub
Substitutions (that occur only once) happen in Hardware
“AD1”.gsub(“AD”, “DA") “AD1”.sub(“AD”, “DA")

12. Example #4 - permute
Permutation happens in Hardware
array.permutation home made solution

13. Example #4 - permute
Permutation happens in Hardware
else { /* this is the general case */
volatile VALUE t0;
long *p = (long*)ALLOCV(t0, r*sizeof(long)+n*sizeof(char));
char *used = (char*)(p + r);
VALUE ary0 = ary_make_shared_copy(ary); /* private defensive copy of ary */
RBASIC_CLEAR_CLASS(ary0);
MEMZERO(used, char, n); /* initialize array */
permute0(n, r, p, used, ary0); /* compute and yield permutations */
ALLOCV_END(t0);
RBASIC_SET_CLASS_RAW(ary0, rb_cArray);
}
return ary;
RECURSIVE STUFF AAAAAAA

14. Example #5 - reverse
reverse happens A LOT in Hardware
reverse reverse! other

15. Example #5 - reverse
reverse happens A LOT in Hardware
static VALUE
rb_ary_reverse_m(VALUE ary)
{
long len = RARRAY_LEN(ary);
VALUE dup = rb_ary_new2(len);
if (len > 0) {
const VALUE *p1 = RARRAY_CONST_PTR(ary);
VALUE *p2 = (VALUE *)RARRAY_CONST_PTR(dup) + len - 1;
do *p2-- = *p1++; while (--len > 0);
}
ARY_SET_LEN(dup, RARRAY_LEN(ary));
return dup;
}
༼ つ ◕_◕ ༽つ༼ つ ◕_◕ ༽つ

16. References
• https://vimeo.com/114848080
• http://chriscontinanza.com/2010/10/29/Array.html
• http://www.cse.dmu.ac.uk/~hgs/ruby/performance/
• https://www.youtube.com/watch?v=fGFM_UrSp70

17. Thanks!!
Questions?
@hannelita
hannelita@gmail.com