On Fri, Feb 07, 2025 at 11:26:50PM -0500, Steven Rostedt wrote: > > Note, even though PREEMPT_RT started in 2004 and wasn't fully merged until > 2024, it slowly did creep in bit by bit. For example, here's a few things that > came from the RT patch, and each was rewritten at least 3 times to become > acceptable by the upstream maintainers: > > - NOHZ > - High res timers > - threaded interrupts > - mutex code (yes, before RT everything used a semaphore) > - lockdep > - ftrace > - generic interrupt code > - generic timer code > - priority inheritance > - SCHED_DEADLINE > - RT push/pull scheduling > > and more. > Here's a little bit of Linux trivia. KVM was first introduced to Linux via the RT patch. Because it was such a new technology and they didn't want to break the Linux workflow, we agreed to take their changes so that they could try out different methods and have users without being committed to something and have their changes break upstream Linux. Sound familiar? -- Steve
