Issue #20197 has been updated by naruse (Yui NARUSE). Backport changed from 3.0: DONTNEED, 3.1: DONTNEED, 3.2: DONTNEED, 3.3: REQUIRED to 3.0: DONTNEED, 3.1: DONTNEED, 3.2: DONTNEED, 3.3: DONE ruby_3_3 0793cbbfde261f4fc9bf7045594d62a21e391811 merged revision(s) ef276858d9295208add48e27208c69184dc50472. ---------------------------------------- Bug #20197: Postponed job invocations are significantly reduced in Ruby 3.3 https://bugs.ruby-lang.org/issues/20197#change-107351 * Author: osyoyu (Daisuke Aritomo) * Status: Closed * Assignee: kjtsanaktsidis (KJ Tsanaktsidis) * ruby -v: ruby 3.3.0 (2023-12-25 revision 5124f9ac75) [x86_64-linux] * Backport: 3.0: DONTNEED, 3.1: DONTNEED, 3.2: DONTNEED, 3.3: DONE ---------------------------------------- The number of postponed job invocations has been significantly reduced in Ruby 3.3. While my understanding is that postponed jobs provide no guarantee of how soon registered callbacks will fire, I believe the current rate is too low for practical usage, especially for profilers such as StackProf. A git bisect led me to https://github.com/ruby/ruby/commit/1f0304218cf00e05a4a126196676ba221ebf91f6 which obviously seems to be related, but I'm not sure why. ## Repro ### Expected The job fires (nearly) immediately after being triggered. In the following example, the job is triggered every 100 ms. ``` % ruby bin/test.rb # runs for 3 seconds count: 1 count: 2 (snip) count: 29 ``` ### Actual The job gets fired only once. ``` % ruby bin/test.rb count: 1 ``` ### Code ```ruby require 'mycext' time = Time.now th = Thread.new do loop do sleep 0.01 break if Time.now - time > 3 # run for 3 seconds end end th.join ``` ```c #include <pthread.h> #include <stdio.h> #include <time.h> #include "ruby.h" #include "ruby/debug.h" int called_count; void postponed_job(void *ptr) { called_count++; printf("count: %d\n", called_count); } _Noreturn void * pthread_main(void *_) { while (1) { rb_postponed_job_register_one(0, postponed_job, NULL); // Sleep for 100 ms struct timespec ts; ts.tv_sec = 0; ts.tv_nsec = 100 * 1000 * 1000; nanosleep(&ts, NULL); } } RUBY_FUNC_EXPORTED void Init_mycext(void) { called_count = 0; pthread_t pthread; pthread_create(&pthread, NULL, pthread_main, NULL); } ``` -- https://bugs.ruby-lang.org/