butcher java virtual threads like a pro

src: Butcher Virtual Threads like a pro! (Piotr PRZYBYL)

Abstract

• Thread.sleep not a real world CPU bound work, so cannot be used to benchmark virtual threads
• corner stone: Virtual threads
  • not reinvent the wheel, keep threads concept
  • cheap to start
  • carried by platform / OS threads under the hood
  • unmounting carrier threads when waiting, e.g. IO
  • always daemons, with normal prio
• car metaphor
  • your own car is a platform thread
  • a taxi is a virtual thread
• virtual threads will not magically squeeze more juice from your CPU!
  • but your application will scale better
• what not to do with virtual threads
  • reuse
  • pool
  • pin
    • -Djdk.tracePinnedThreads=full and JFR events to detect pinning issues
• logging is IO operation, so it can play on the virtual thread performance
  • when monitoring virtual threads, do not use IO operation like logs
• scoped values
  • one-way immutable ThreadLocals + bounded lifetime
  • simplified reasoning and improved performance
  • work nicely with structured concurrenvy
  • don’t use mutable variables
• structured concurrency
  • subtasks should be interruptible