Dmitrij Vlasov

Senior software engineer with solid commercial software development experience,
good team leadership experience and primary focus on BE (Ruby).

less than 1 minute read

Concurrency vs parallelism, threads/fibers/ractors(guilds), blocking/non-blocking I/O etc

parallelism:

  • <3.0: only with threads + JRuby/rubinius (GIL makes parallelism impossible in CRuby)
  • since 3.0 - ractors/guilds

concurrency:

  • threads (implicit concurrency)
  • fibers (developer manipulates concurrency explicitly)

non-blocking I/O:

  • before: run multiple threads (they are smart enough to pass execution to another thread when blocking I/O occurs)
  • now: use async gem - uses fibers + fiber scheduler (introduced in ruby 3), so it’s much more fast/lightweight