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rubyruby-2.6

Which ruby methods free GVL?

In multi-threaded ruby execution, you cannot get parallel execution of threads unless you use those functions which frees GVL.

In my understanding, following ruby methods frees GVL:

  • Kernel#sleep
  • IO#read and IO#write

Question

  • In pure ruby, is there any other methods which frees GVL?

Version

  • I'm currently using ruby version 2.6, so expect the info of this version.
Solution

  • I asked same question on stackoverflow (Japanese).

    Got this answer https://ja.stackoverflow.com/a/55579/754 , which stating that

    • Bignum's div / modulo
    • Dir.new/Dir.open
    • Dir.chdir
    • Dir.rmdir
    • Dir.empty?
    • Dir.glob
    • File.chown
    • File's methods which check file status, namely stats
    • File.rename
    • File.truncate
    • File.mkfifo
    • IO.copy_stream
    • IO.#open and IO.#close related codes (was too complex to understand)
    • Kernel.#system
    • Kernel.#exec

    and in other standard libraries such as fiddle, openssl, readline, socket, zlib actually calls method which frees GVL.

    this great answer was written by https://stackoverflow.com/users/4944814/raccy