Ruby

Abstract¶

Within #to_binary, deduplication of objects output to binary is performed, but the current implementation is achieved by a linear search of an array of objects (=obj_list). (https://github.com/ruby/ruby/blob/e288632f22b18b29efd20a1469292b0a3ba9b74c/compile.c#L9699-L9701)
On the other hand, iseq deduplication is faster because it is implemented using a hash. (https://github.com/ruby/ruby/blob/e288632f22b18b29efd20a1469292b0a3ba9b74c/compile.c#L9744-L9745)

This proposal speeds up object deduplication by using a hash.
This patch does not change the output binary.

Implementation¶

https://github.com/ruby/ruby/pull/2835

Evaluation¶

Environment:

• OS: macOS Catalina
• CPU: Intel Core i5
• Memory: 16GB

address_lists_parser.rb¶

address_lists_parser.rb(https://github.com/mikel/mail/blob/master/lib/mail/parsers/address_lists_parser.rb) in mail gem has an extremely huge array.
Call # to_binary on the iseq of this file and check its execution time and MD5 of the output binary.

The benchmark code:

require 'benchmark' require 'digest/md5' F = 'address_lists_parser.rb' N = 100 iseq = RubyVM::InstructionSequence.compile_file(F) bin = iseq.to_binary puts "md5 hash: #{Digest::MD5.hexdigest(bin)}" Benchmark.bm(12) do |x| x.report("to_binary x#{N}") { N.times do || iseq.to_binary end } end 

• master (ruby 2.8.0dev (2020-01-12T10:54:59Z master e288632f22) [x86_64-darwin19])

  md5 hash: fd80e7c0c8da7a9044e89139c6078137 user system total real to_binary x100 27.162084 0.078262 27.240346 ( 27.675089) 

• Proposal (ruby 2.8.0dev (2020-01-12T12:39:10Z improve-performanc.. e05ad5ef81) [x86_64-darwin19])

  md5 hash: fd80e7c0c8da7a9044e89139c6078137 user system total real to_binary x100 0.989403 0.036869 1.026272 ( 1.063335) 

The same binary was output before and after the change.
Execution speed is 26 times faster.