SLOMO

No one wants to be stuck in the slow lane, especially Rubyists. In this talk we'll look at the slow process of writing fast code. We'll look at several real world performance optimizations that may surprise you. We'll then rewind to see how these slow spots were found and fixed. Come to this talk and we will "C" how fast your Ruby can "Go".

Transcript

3. slomo the movie www. .com Special thanks
4. Introducing Dr. John Kitchin The neurologist
5. Introducing Dr. John Kitchin The inspiration
6. Introducing Dr. John Kitchin The skater
7. What is your goal in life?
8. Grow up
9. Pick a career
10. Buy a sports car
11. Retire
12. The faster the better
13. Slomo
14. Said “no”
15. Introducing Schneems The narrator
16. Sounds like “schnapps”
17. The narrator said, explaining his own introduction
20. Maintain Sprockets
21. Those are all my hobbies
22. Full time job:
23. Resisting the Trump Administration
24. I consider myself a very chill person
25. Like to mix my yoga habits with resistance
26. “ohm”
27. BTW
28. In this talk we will not use “nil”
29. Naan
30. Sorry for ny naan jokes
31. Sorry for ny naan jokes
32. This
33. talk
34. is
35. about
36. speed
38. The fastest way to get where you’re going
39. Depends on where you’re going
40. To get there faster
41. Let’s slow down
42. Why would we want slower code?
43. Measure it
44. task "assets:profile" do puts "==============" StackProf.run(mode: :wall, out: "tmp/stackprof.dump") do Rake::Task["assets:precompile"].invoke end puts "Running: $ stackprof tmp/stackprof.dump" puts `stackprof tmp/stackprof.dump` end
45. task "assets:profile" do puts "==============" StackProf.run(mode: :wall, out: "tmp/stackprof.dump") do Rake::Task["assets:precompile"].invoke end puts "Running: $ stackprof tmp/stackprof.dump" puts `stackprof tmp/stackprof.dump` end
46. task "assets:profile" do puts "==============" StackProf.run(mode: :wall, out: "tmp/stackprof.dump") do Rake::Task["assets:precompile"].invoke end puts "Running: $ stackprof tmp/stackprof.dump" puts `stackprof tmp/stackprof.dump` end
47. $ stackprof tmp/stackprof.dump
48. Running: $ stackprof tmp/stackprof.dump ================================== Mode: wall(1000) Samples: 2083 (62.23% miss rate) GC: 282 (13.54%) ================================== TOTAL (pct) SAMPLES (pct) FRAME 313 (15.0%) 313 (15.0%) Set#include? 307 (14.7%) 243 (11.7%) Sprockets::DigestUtils#digest 743 (35.7%) 137 (6.6%) Kernel#require 476 (22.9%) 124 (6.0%) Kernel#require 157 (7.5%) 92 (4.4%) SassC::Rails::Importer#imports 243 (11.7%) 81 (3.9%) #<Module:0x007fc76f34eb10> 67 (3.2%) 67 (3.2%) NumericWithFormat#to_s 160 (7.7%) 53 (2.5%) PathUtils#atomic_write 44 (2.1%) 44 (2.1%) #<Module:0x007fc76bdfb558> 239 (11.5%) 37 (1.8%) Sprockets::Cache::FileStore#set
49. Running: $ stackprof tmp/stackprof.dump ================================== Mode: wall(1000) Samples: 2083 (62.23% miss rate) GC: 282 (13.54%) ================================== TOTAL (pct) SAMPLES (pct) FRAME 313 (15.0%) 313 (15.0%) Set#include? 307 (14.7%) 243 (11.7%) Sprockets::DigestUtils#digest 743 (35.7%) 137 (6.6%) Kernel#require 476 (22.9%) 124 (6.0%) Kernel#require 157 (7.5%) 92 (4.4%) SassC::Rails::Importer#imports 243 (11.7%) 81 (3.9%) #<Module:0x007fc76f34eb10> 67 (3.2%) 67 (3.2%) NumericWithFormat#to_s 160 (7.7%) 53 (2.5%) PathUtils#atomic_write 44 (2.1%) 44 (2.1%) #<Module:0x007fc76bdfb558> 239 (11.5%) 37 (1.8%) Sprockets::Cache::FileStore#set Class and method
50. Running: $ stackprof tmp/stackprof.dump ================================== Mode: wall(1000) Samples: 2083 (62.23% miss rate) GC: 282 (13.54%) ================================== TOTAL (pct) SAMPLES (pct) FRAME 313 (15.0%) 313 (15.0%) Set#include? 307 (14.7%) 243 (11.7%) Sprockets::DigestUtils#digest 743 (35.7%) 137 (6.6%) Kernel#require 476 (22.9%) 124 (6.0%) Kernel#require 157 (7.5%) 92 (4.4%) SassC::Rails::Importer#imports 243 (11.7%) 81 (3.9%) #<Module:0x007fc76f34eb10> 67 (3.2%) 67 (3.2%) NumericWithFormat#to_s 160 (7.7%) 53 (2.5%) PathUtils#atomic_write 44 (2.1%) 44 (2.1%) #<Module:0x007fc76bdfb558> 239 (11.5%) 37 (1.8%) Sprockets::Cache::FileStore#set Total # of samples
51. Running: $ stackprof tmp/stackprof.dump ================================== Mode: wall(1000) Samples: 2083 (62.23% miss rate) GC: 282 (13.54%) ================================== TOTAL (pct) SAMPLES (pct) FRAME 313 (15.0%) 313 (15.0%) Set#include? 307 (14.7%) 243 (11.7%) Sprockets::DigestUtils#digest 743 (35.7%) 137 (6.6%) Kernel#require 476 (22.9%) 124 (6.0%) Kernel#require 157 (7.5%) 92 (4.4%) SassC::Rails::Importer#imports 243 (11.7%) 81 (3.9%) #<Module:0x007fc76f34eb10> 67 (3.2%) 67 (3.2%) NumericWithFormat#to_s 160 (7.7%) 53 (2.5%) PathUtils#atomic_write 44 (2.1%) 44 (2.1%) #<Module:0x007fc76bdfb558> 239 (11.5%) 37 (1.8%) Sprockets::Cache::FileStore#set Percentage
52. Running: $ stackprof tmp/stackprof.dump ================================== Mode: wall(1000) Samples: 2083 (62.23% miss rate) GC: 282 (13.54%) ================================== TOTAL (pct) SAMPLES (pct) FRAME 313 (15.0%) 313 (15.0%) Set#include? 307 (14.7%) 243 (11.7%) Sprockets::DigestUtils#digest 743 (35.7%) 137 (6.6%) Kernel#require 476 (22.9%) 124 (6.0%) Kernel#require 157 (7.5%) 92 (4.4%) SassC::Rails::Importer#imports 243 (11.7%) 81 (3.9%) #<Module:0x007fc76f34eb10> 67 (3.2%) 67 (3.2%) NumericWithFormat#to_s 160 (7.7%) 53 (2.5%) PathUtils#atomic_write 44 (2.1%) 44 (2.1%) #<Module:0x007fc76bdfb558> 239 (11.5%) 37 (1.8%) Sprockets::Cache::FileStore#set Total at TOP of stack
53. Running: $ stackprof tmp/stackprof.dump ================================== Mode: wall(1000) Samples: 2083 (62.23% miss rate) GC: 282 (13.54%) ================================== TOTAL (pct) SAMPLES (pct) FRAME 313 (15.0%) 313 (15.0%) Set#include? 307 (14.7%) 243 (11.7%) Sprockets::DigestUtils#digest 743 (35.7%) 137 (6.6%) Kernel#require 476 (22.9%) 124 (6.0%) Kernel#require 157 (7.5%) 92 (4.4%) SassC::Rails::Importer#imports 243 (11.7%) 81 (3.9%) #<Module:0x007fc76f34eb10> 67 (3.2%) 67 (3.2%) NumericWithFormat#to_s 160 (7.7%) 53 (2.5%) PathUtils#atomic_write 44 (2.1%) 44 (2.1%) #<Module:0x007fc76bdfb558> 239 (11.5%) 37 (1.8%) Sprockets::Cache::FileStore#set Percent at TOP of stack
54. Running: $ stackprof tmp/stackprof.dump ================================== Mode: wall(1000) Samples: 2083 (62.23% miss rate) GC: 282 (13.54%) ================================== TOTAL (pct) SAMPLES (pct) FRAME 313 (15.0%) 313 (15.0%) Set#include? 307 (14.7%) 243 (11.7%) Sprockets::DigestUtils#digest 743 (35.7%) 137 (6.6%) Kernel#require 476 (22.9%) 124 (6.0%) Kernel#require 157 (7.5%) 92 (4.4%) SassC::Rails::Importer#imports 243 (11.7%) 81 (3.9%) #<Module:0x007fc76f34eb10> 67 (3.2%) 67 (3.2%) NumericWithFormat#to_s 160 (7.7%) 53 (2.5%) PathUtils#atomic_write 44 (2.1%) 44 (2.1%) #<Module:0x007fc76bdfb558> 239 (11.5%) 37 (1.8%) Sprockets::Cache::FileStore#set
55. 26% of total execution samples
56. What is calling so much? Set#include?
57. $ stackprof tmp/stackprof.dump --method Set#include? Set#include? (/Users/richardschneeman/.rubies/ruby-2.3.1/lib/ruby/2.3.0/set.rb:214) samples: 313 self (15.0%) / 313 total (15.0%) callers: 312 ( 99.7%) Sprockets::ProcessorUtils#valid_processor_metadata_value? 1 ( 0.3%) Sprockets::Utils#dfs_paths code: | 214 | def include?(o) 313 (15.0%) / 313 (15.0%) | 215 | @hash[o] | 216 | end
58. $ stackprof tmp/stackprof.dump --method Set#include? Set#include? (/Users/richardschneeman/.rubies/ruby-2.3.1/lib/ruby/2.3.0/set.rb:214) samples: 313 self (15.0%) / 313 total (15.0%) callers: 312 ( 99.7%) Sprockets::ProcessorUtils#valid_processor_metadata_value? 1 ( 0.3%) Sprockets::Utils#dfs_paths code: | 214 | def include?(o) 313 (15.0%) / 313 (15.0%) | 215 | @hash[o] | 216 | end
59. What is calling so much? valid_processor_metadata_value?
60. $ stackprof tmp/stackprof.dump --method Sprockets::ProcessorUtils#valid_processor_metadata_value? Sprockets::ProcessorUtils#valid_processor_metadata_value? (/Users/richardschneeman/.gem/ruby/2.3.1/bundler/ gems/sprockets-3b0d6732c13f/lib/sprockets/processor_utils.rb:170) samples: 24 self (1.2%) / 2129 total (102.2%) callers: 1793 ( 84.2%) Sprockets::ProcessorUtils#valid_processor_metadata_value? 336 ( 15.8%) Sprockets::ProcessorUtils#validate_processor_result! callees (2105 total): 1793 ( 85.2%) Sprockets::ProcessorUtils#valid_processor_metadata_value? 312 ( 14.8%) Set#include? code: | 170 | def valid_processor_metadata_value?(value) 261 (12.5%) / 2 (0.1%) | 171 | if VALID_METADATA_VALUE_TYPES.include?(value.class) | 172 | true 61 (2.9%) / 8 (0.4%) | 173 | elsif VALID_METADATA_COMPOUND_TYPES.include?(value.class) 1806 (86.7%) / 13 (0.6%) | 174 | value.all? { |v| valid_processor_metadata_value?(v) } | 175 | else 1 (0.0%) / 1 (0.0%) | 176 | false | 177 | end
61. $ stackprof tmp/stackprof.dump --method Sprockets::ProcessorUtils#valid_processor_metadata_value? Sprockets::ProcessorUtils#valid_processor_metadata_value? (/Users/richardschneeman/.gem/ruby/2.3.1/bundler/ gems/sprockets-3b0d6732c13f/lib/sprockets/processor_utils.rb:170) samples: 24 self (1.2%) / 2129 total (102.2%) callers: 1793 ( 84.2%) Sprockets::ProcessorUtils#valid_processor_metadata_value? 336 ( 15.8%) Sprockets::ProcessorUtils#validate_processor_result! callees (2105 total): 1793 ( 85.2%) Sprockets::ProcessorUtils#valid_processor_metadata_value? 312 ( 14.8%) Set#include? code: | 170 | def valid_processor_metadata_value?(value) 261 (12.5%) / 2 (0.1%) | 171 | if VALID_METADATA_VALUE_TYPES.include?(value.class) | 172 | true 61 (2.9%) / 8 (0.4%) | 173 | elsif VALID_METADATA_COMPOUND_TYPES.include?(value.class) 1806 (86.7%) / 13 (0.6%) | 174 | value.all? { |v| valid_processor_metadata_value?(v) } | 175 | else 1 (0.0%) / 1 (0.0%) | 176 | false | 177 | end
62. $ stackprof tmp/stackprof.dump --method Sprockets::ProcessorUtils#valid_processor_metadata_value? Sprockets::ProcessorUtils#valid_processor_metadata_value? (/Users/richardschneeman/.gem/ruby/2.3.1/bundler/ gems/sprockets-3b0d6732c13f/lib/sprockets/processor_utils.rb:170) samples: 24 self (1.2%) / 2129 total (102.2%) callers: 1793 ( 84.2%) Sprockets::ProcessorUtils#valid_processor_metadata_value? 336 ( 15.8%) Sprockets::ProcessorUtils#validate_processor_result! callees (2105 total): 1793 ( 85.2%) Sprockets::ProcessorUtils#valid_processor_metadata_value? 312 ( 14.8%) Set#include? code: | 170 | def valid_processor_metadata_value?(value) 261 (12.5%) / 2 (0.1%) | 171 | if VALID_METADATA_VALUE_TYPES.include?(value.class) | 172 | true 61 (2.9%) / 8 (0.4%) | 173 | elsif VALID_METADATA_COMPOUND_TYPES.include?(value.class) 1806 (86.7%) / 13 (0.6%) | 174 | value.all? { |v| valid_processor_metadata_value?(v) } | 175 | else 1 (0.0%) / 1 (0.0%) | 176 | false | 177 | end
63. def valid_processor_metadata_value?(value) if VALID_METADATA_VALUE_TYPES.include?(value.class) true elsif VALID_METADATA_COMPOUND_TYPES.include?(value.class) value.all? { |v| valid_processor_metadata_value?(v) } else false end end
64. Set#include?
65. # File set.rb, line 214 def include?(o) @hash[o] end
66. Set is powered by a Hash under the hood
67. Skip the Set, just use a Hash
68. But why?
69. Ruby has optimized instructions for hash calls
70. code = " foo = Hash.new foo[:bar] " puts RubyVM::InstructionSequence.compile(code).disasm # 0000 trace 1 ( 2) # 0002 getinlinecache 9, <is:0> # 0005 getconstant :Hash # 0007 setinlinecache <is:0> # 0009 opt_send_without_block <callinfo!mid:new, argc:0, ARGS_SIMPLE>, <callcache> # 0012 setlocal_OP__WC__0 2 # 0014 trace 1 ( 3) # 0016 getlocal_OP__WC__0 2 # 0018 putobject :bar # 0020 opt_aref <callinfo!mid:[], argc:1, ARGS_SIMPLE>, <callcache> # 0023 leave
71. Compare to Set
72. code = " s = Set.new s.include?(:bar) " puts RubyVM::InstructionSequence.compile(code).disasm # 0000 trace 1 ( 2) # 0002 getinlinecache 9, <is:0> # 0005 getconstant :Set # 0007 setinlinecache <is:0> # 0009 opt_send_without_block <callinfo!mid:new, argc:0, ARGS_SIMPLE>, <callcache> # 0012 setlocal_OP__WC__0 2 # 0014 trace 1 ( 3) # 0016 getlocal_OP__WC__0 2 # 0018 putobject :bar # 0020 opt_send_without_block <callinfo!mid:include?, argc:1, ARGS_SIMPLE>, <callcache> # 0023 leave
74. insns.def
75. /** @c optimize @e [] @j 最適化された recv[obj]。 */ DEFINE_INSN opt_aref (CALL_INFO ci, CALL_CACHE cc) (VALUE recv, VALUE obj) (VALUE val) { if (!SPECIAL_CONST_P(recv)) { if (RBASIC_CLASS(recv) == rb_cArray && BASIC_OP_UNREDEFINED_P(BOP_AREF, ARRAY_REDEFINED_OP_FLAG) && FIXNUM_P(obj)) { val = rb_ary_entry(recv, FIX2LONG(obj)); } else if (RBASIC_CLASS(recv) == rb_cHash && BASIC_OP_UNREDEFINED_P(BOP_AREF, HASH_REDEFINED_OP_FLAG)) { val = rb_hash_aref(recv, obj); } else { goto INSN_LABEL(normal_dispatch); } } else { INSN_LABEL(normal_dispatch): PUSH(recv); PUSH(obj); CALL_SIMPLE_METHOD(recv); } }
76. /** @c optimize @e [] @j 最適化された recv[obj]。 */ DEFINE_INSN opt_aref (CALL_INFO ci, CALL_CACHE cc) (VALUE recv, VALUE obj) (VALUE val) { if (!SPECIAL_CONST_P(recv)) { if (RBASIC_CLASS(recv) == rb_cArray && BASIC_OP_UNREDEFINED_P(BOP_AREF, ARRAY_REDEFINED_OP_FLAG) && FIXNUM_P(obj)) { val = rb_ary_entry(recv, FIX2LONG(obj)); } else if (RBASIC_CLASS(recv) == rb_cHash && BASIC_OP_UNREDEFINED_P(BOP_AREF, HASH_REDEFINED_OP_FLAG)) { val = rb_hash_aref(recv, obj); } else { goto INSN_LABEL(normal_dispatch); } } else { INSN_LABEL(normal_dispatch): PUSH(recv); PUSH(obj); CALL_SIMPLE_METHOD(recv); } }
77. Versus
78. /** @c optimize @e Invoke method without block @j Invoke method without block */ DEFINE_INSN opt_send_without_block (CALL_INFO ci, CALL_CACHE cc) (...) (VALUE val) // inc += -ci->orig_argc; { struct rb_calling_info calling; calling.blockptr = NULL; vm_search_method(ci, cc, calling.recv = TOPN(calling.argc = ci->orig_argc)); CALL_METHOD(&calling, ci, cc); }
79. /** @c optimize @e Invoke method without block @j Invoke method without block */ DEFINE_INSN opt_send_without_block (CALL_INFO ci, CALL_CACHE cc) (...) (VALUE val) // inc += -ci->orig_argc; { struct rb_calling_info calling; calling.blockptr = NULL; vm_search_method(ci, cc, calling.recv = TOPN(calling.argc = ci->orig_argc)); CALL_METHOD(&calling, ci, cc); }
80. Ruby optimizes Hash calls by Skipping Method Lookup
81. BTW
82. Don’t subclass Hash
83. /** @c optimize @e [] @j 最適化された recv[obj]。 */ DEFINE_INSN opt_aref (CALL_INFO ci, CALL_CACHE cc) (VALUE recv, VALUE obj) (VALUE val) { if (!SPECIAL_CONST_P(recv)) { if (RBASIC_CLASS(recv) == rb_cArray && BASIC_OP_UNREDEFINED_P(BOP_AREF, ARRAY_REDEFINED_OP_FLAG) && FIXNUM_P(obj)) { val = rb_ary_entry(recv, FIX2LONG(obj)); } else if (RBASIC_CLASS(recv) == rb_cHash && BASIC_OP_UNREDEFINED_P(BOP_AREF, HASH_REDEFINED_OP_FLAG)) { val = rb_hash_aref(recv, obj); } else { goto INSN_LABEL(normal_dispatch); } } else { INSN_LABEL(normal_dispatch): PUSH(recv); PUSH(obj); CALL_SIMPLE_METHOD(recv); } } You lose speed
84. 
 “I don’t subclass hash”
85. Hash With Indifferent Access
86. Hashie
87. Rack:: Utils::
 HeaderHash
89. Rack is 23% faster without HeaderHash
90. Don’t subclass Hash
92. Switch Set to a hash
93. VALID_METADATA_VALUE_TYPES_HASH = VALID_METADATA_VALUE_TYPES. each_with_object({}) do |type, hash| hash[type] = true end.freeze def valid_processor_metadata_value?(value) if VALID_METADATA_VALUE_TYPES_HASH[value.class] true elsif VALID_METADATA_COMPOUND_TYPES_HASH[value.class] value.all? { |v| valid_processor_metadata_value?(v) } else false end end
94. Skips Method Lookup
95. Did it help?
96. 18.325s 17.981s
97. 1.8% Faster!
98. Bugger
100. Keep gliding
101. Round 2
102. TOTAL (pct) SAMPLES (pct) FRAME 2328 (109.6%) 362 (17.0%) Sprockets::ProcessorUtils# valid_processor_metadata_value? 348 (16.4%) 256 (12.1%) Sprockets::DigestUtils#digest 486 (22.9%) 106 (5.0%) Kernel#require 97 (4.6%) 97 (4.6%) ActiveSupport:: NumericWithFormat#to_s 123 (5.8%) 94 (4.4%) Sprockets::PathUtils#atomic_write 581 (27.4%) 76 (3.6%) Kernel#require 61 (2.9%) 61 (2.9%) #<Module:0x007fb0a6027728> .mechanism 193 (9.1%) 52 (2.4%) Sprockets::Cache::FileStore#set 95 (4.5%) 48 (2.3%) SassC::Rails::Importer# imports 36 (1.7%) 36 (1.7%) ExecJS::ExternalRuntime# exec_runtime 59 (2.8%) 25 (1.2%) Kernel#require 75 (3.5%) 25 (1.2%) Module#delegate
103. $ stackprof tmp/stackprof.dump --method Sprockets::DigestUtils#digest # . . . Sprockets::DigestUtils#digest (lib/sprockets/digest_utils.rb:46) samples: 4 self (0.2%) / 7 total (0.3%) callers: 5 ( 71.4%) Sprockets::Cache#expand_key 2 ( 28.6%) Sprockets::Loader#load_from_unloaded callees (3 total): 3 ( 100.0%) Sprockets::DigestUtils#digest_class code: | 46 | def digest(obj) 4 (0.2%) / 1 (0.0%) | 47 | digest = digest_class.new | 48 | queue = [obj] | 49 | | 50 | while queue.length > 0 | 51 | obj = queue.shift | 52 | klass = obj.class | 53 | 2 (0.1%) / 2 (0.1%) | 54 | if klass == String | 55 | digest << obj | 56 | elsif klass == Symbol | 57 | digest << 'Symbol' | 58 | digest << obj.to_s | 59 | elsif klass == Fixnum
104. $ stackprof tmp/stackprof.dump --method Sprockets::DigestUtils#digest # . . . Sprockets::DigestUtils#digest (lib/sprockets/digest_utils.rb:46) samples: 4 self (0.2%) / 7 total (0.3%) callers: 5 ( 71.4%) Sprockets::Cache#expand_key 2 ( 28.6%) Sprockets::Loader#load_from_unloaded callees (3 total): 3 ( 100.0%) Sprockets::DigestUtils#digest_class code: | 46 | def digest(obj) 4 (0.2%) / 1 (0.0%) | 47 | digest = digest_class.new | 48 | queue = [obj] | 49 | | 50 | while queue.length > 0 | 51 | obj = queue.shift | 52 | klass = obj.class | 53 | 2 (0.1%) / 2 (0.1%) | 54 | if klass == String | 55 | digest << obj | 56 | elsif klass == Symbol | 57 | digest << 'Symbol' | 58 | digest << obj.to_s | 59 | elsif klass == Fixnum
105. def digest(obj) digest = digest_class.new queue = [obj] while queue.length > 0 obj = queue.shift klass = obj.class if klass == String digest << obj elsif klass == Symbol digest << 'Symbol' digest << obj.to_s elsif klass == Fixnum digest << 'Fixnum' digest << obj.to_s elsif klass == Bignum digest << 'Bignum' digest << obj.to_s elsif klass == TrueClass digest << 'TrueClass' elsif klass == FalseClass digest << 'FalseClass'
106. Let me paraphrase
107. if String
108. if String elsif Symbol
109. if String elsif Symbol elsif Fixnum
110. if String elsif Symbol elsif Fixnum elsif Bignum
111. if String elsif Symbol elsif Fixnum elsif Bignum elsif TrueClass
112. if String elsif Symbol elsif Fixnum elsif Bignum elsif TrueClass elsif FalseClass
113. if String elsif Symbol elsif Fixnum elsif Bignum elsif TrueClass elsif FalseClass elsif NilClass
114. if String elsif Symbol elsif Fixnum elsif Bignum elsif TrueClass elsif FalseClass elsif NilClass elsif Array
115. if String elsif Symbol elsif Fixnum elsif Bignum elsif TrueClass elsif FalseClass elsif NilClass elsif Array elsif Hash
116. if String elsif Symbol elsif Fixnum elsif Bignum elsif TrueClass elsif FalseClass elsif NilClass elsif Array elsif Hash elsif Set
117. if String elsif Symbol elsif Fixnum elsif Bignum elsif TrueClass elsif FalseClass elsif NilClass elsif Array elsif Hash elsif Set elsif Encoding
118. If we pass in a Set object, we must make 10 comparisons
119. if String elsif Symbol elsif Fixnum elsif Bignum elsif TrueClass elsif FalseClass elsif NilClass elsif Array elsif Hash elsif Set elsif Encoding Expand and Iterate
120. if/elsif is hidden iteration
121. How do we go faster?
122. Get rid of iteration
123. Case statements
124. or
125. Hash loOkups
126. Before
127. def digest(obj) digest = digest_class.new queue = [obj] while queue.length > 0 obj = queue.shift klass = obj.class if klass == String digest << obj elsif klass == Symbol digest << 'Symbol' digest << obj.to_s elsif klass == Fixnum digest << 'Fixnum' digest << obj.to_s elsif klass == Bignum digest << 'Bignum' digest << obj.to_s elsif klass == TrueClass digest << 'TrueClass' elsif klass == FalseClass digest << 'FalseClass' elsif klass == NilClass digest << 'NilClass'.freeze elsif klass == Array digest << 'Array' queue.concat(obj) elsif klass == Hash digest << 'Hash' queue.concat(obj.sort) elsif klass == Set digest << 'Set' queue.concat(obj.to_a) elsif klass == Encoding digest << 'Encoding' digest << obj.name else raise TypeError, "couldn't digest #{klass}" end end digest.digest end
128. After
129. def digest(obj) digest = digest_class.new ADD_VALUE_TO_DIGEST[obj.class].call(obj, digest) digest.digest end
130. Store logic in a Hash
131. def digest(obj) digest = digest_class.new ADD_VALUE_TO_DIGEST[obj.class].call(obj, digest) digest.digest end Constant time lookup
132. Logic Lives in Lambdas
133. ADD_VALUE_TO_DIGEST = { String => ->(val, digest) { digest << val }, FalseClass => ->(val, digest) { digest << 'FalseClass'.freeze }, TrueClass => ->(val, digest) { digest << 'TrueClass'.freeze }, NilClass => ->(val, digest) { digest << 'NilClass'.freeze }, Symbol => ->(val, digest) { digest << 'Symbol'.freeze digest << val.to_s }, Integer => ->(val, digest) { digest << 'Integer'.freeze digest << val.to_s }, Array => ->(val, digest) { digest << 'Array'.freeze val.each do |element| ADD_VALUE_TO_DIGEST[element.class].call(element, digest) end },
134. ADD_VALUE_TO_DIGEST = { String => ->(val, digest) { digest << val }, FalseClass => ->(val, digest) { digest << 'FalseClass'.freeze }, TrueClass => ->(val, digest) { digest << 'TrueClass'.freeze }, NilClass => ->(val, digest) { digest << 'NilClass'.freeze }, Symbol => ->(val, digest) { digest << 'Symbol'.freeze digest << val.to_s }, Integer => ->(val, digest) { digest << 'Integer'.freeze digest << val.to_s }, Array => ->(val, digest) { digest << 'Array'.freeze val.each do |element| ADD_VALUE_TO_DIGEST[element.class].call(element, digest) end },
135. ADD_VALUE_TO_DIGEST = { String => ->(val, digest) { digest << val }, FalseClass => ->(val, digest) { digest << 'FalseClass'.freeze }, TrueClass => ->(val, digest) { digest << 'TrueClass'.freeze }, NilClass => ->(val, digest) { digest << 'NilClass'.freeze }, Symbol => ->(val, digest) { digest << 'Symbol'.freeze digest << val.to_s }, Integer => ->(val, digest) { digest << 'Integer'.freeze digest << val.to_s }, Array => ->(val, digest) { digest << 'Array'.freeze val.each do |element| ADD_VALUE_TO_DIGEST[element.class].call(element, digest) end },
136. ADD_VALUE_TO_DIGEST = { String => ->(val, digest) { digest << val }, FalseClass => ->(val, digest) { digest << 'FalseClass'.freeze }, TrueClass => ->(val, digest) { digest << 'TrueClass'.freeze }, NilClass => ->(val, digest) { digest << 'NilClass'.freeze }, Symbol => ->(val, digest) { digest << 'Symbol'.freeze digest << val.to_s }, Integer => ->(val, digest) { digest << 'Integer'.freeze digest << val.to_s }, Array => ->(val, digest) { digest << 'Array'.freeze val.each do |element| ADD_VALUE_TO_DIGEST[element.class].call(element, digest) end },
137. zOMG WAT
138. Recursive hash is Recursive
139. Faster?
140. 14.9s 12.54s
141. 16% faster asset compilation with no cache
142. Repeat for all supported types
143. Who likes audience participation?
144. Can we go faster?
145. ADD_VALUE_TO_DIGEST[String] ADD_VALUE_TO_DIGEST[Hash] ADD_VALUE_TO_DIGEST[true] ADD_VALUE_TO_DIGEST[false] ADD_VALUE_TO_DIGEST[nil] ADD_VALUE_TO_DIGEST[Array] ADD_VALUE_TO_DIGEST[Set] ADD_VALUE_TO_DIGEST[Integer]
146. String Hash true false nil Array Set Integer All Constants
147. Hash# compare_by_identity
148. Compare object, not value
149. String Hash true false nil Array Set Integer All Constants
151. 7% speed improvement
152. Let’s slow it down
153. What did we do?
154. Identify a goal
157. Gather potentially useful tools
162. Iterate on the problem
167. RubyVM::InstructionSequence.compile(code).disasm
168. Shoulders of giants
170. The more you understand about _how_ your code works, the faster you can make it
171. Find a speed buddy
172. (or buddies)
173. “C” how fast your program will go
174. gem 'sassc-rails'
175. Sassc uses libsass
176. 31% faster
177. Sprockets 4 will support sassc out of the box (but not yet)
178. Don’t abandon your language for speed
179. Find the slow parts and tag team them with other languages
180. C-extensions
181. Use Rust with helix
182. Use Go with gorb
183. p.s. have you tried JRuby?
184. What about cached compile times
186. Bootscale caches require lookups
187. Without it, the more gems on your system the LONGER `require` takes
188. 6s cached compile times 2s cached compile times
189. 300% faster
191. Don’t be an asshole
192. Don’t appologize for the programing language you love
193. Set your own goals
194. Go at your own speed
195. These are the good days of our programming life
196. Live them to the fullest