November 2024 - ruby-core - ml.ruby-lang.org

[ruby-core:119683] [Ruby master Feature#20861] Add an environment variable for tuning the default thread quantum
by tenderlovemaking (Aaron Patterson) 08 Jun '25

08 Jun '25

Issue #20861 has been reported by tenderlovemaking (Aaron Patterson). ---------------------------------------- Feature #20861: Add an environment variable for tuning the default thread quantum https://bugs.ruby-lang.org/issues/20861 * Author: tenderlovemaking (Aaron Patterson) * Status: Open ---------------------------------------- The default thread quantum is currently [hard coded at 100ms](https://github.com/ruby/ruby/blob/c7708d22c33040a74ea7ac683bf7407d37…. This can impact multithreaded systems that are trying to process Ruby level CPU bound work at the same time as IO work. I would like to add an environment variable `RUBY_THREAD_DEFAULT_QUANTUM_MS` that allows users to specify the default thread quantum (in milliseconds) via an environment variable. It defaults to our current default of 100ms. I've submitted the patch [here](https://github.com/ruby/ruby/pull/11981). Here is a Ruby program to demonstrate the problem: ```ruby def measure x = Process.clock_gettime(Process::CLOCK_MONOTONIC) yield Process.clock_gettime(Process::CLOCK_MONOTONIC) - x end def fib(n) if n < 2 n else fib(n-2) + fib(n-1) end end # find fib that takes ~500ms fib_i = 50.times.find { |i| measure { fib(i) } >= 0.05 } sleep_i = measure { fib(fib_i) } threads = [ Thread.new { 100.times { sleep(sleep_i) # sometimes stalled waiting for fib's quantum to finish } puts "done 1" }, Thread.new { 100.times { fib(fib_i) }; puts "done 2" }, ] # We expect the total time to be about 100 * sleep_i (~5 seconds) because # theoretically the sleep thread could be done nearly completely in parallel to # the fib thread. # # But because the `sleep` thread is iterating over the sleep call, it must wait # for the `fib` thread to complete its quantum, before it can start the next iteration. # # This means each sleep iteration could take up to `sleep_i + 100ms` # # We're calling that stalled time "waste" total = measure { threads.each(&:join) } waste = total - (sleep_i * 100) p TOTAL: total, WASTE: waste ``` The program has two threads. One thread is using CPU time by computing `fib` in a loop. The other thread is simulating IO time by calling `sleep` in a loop. When the `sleep` call completes, it can stall, waiting for the quantum in the fib thread to expire. That means that each iteration on sleep can actually take `sleep time + thread quantum`, or in this case ~600ms when we expected it to only take ~500ms. Ideally, the above program would take `500ms * 100` since all `sleep` calls should be able to execute in parallel with the `fib` calls. Of course this isn't true because the sleep thread must acquire the GVL before it can continue the next iteration, so there will always be _some_ overhead. This feature is for allowing people to tune that overhead. If we run this program with the default quantum the output looks like this: ``` $ ./miniruby -v fibtest.rb ruby 3.4.0dev (2024-11-01T14:49:50Z quantum-computing c7708d22c3) +PRISM [arm64-darwin24] done 2 done 1 {TOTAL: 12.672821999993175, WASTE: 4.960721996147186} ``` The output shows that our program spent about 5 seconds stalled, waiting to acquire the GVL. With this patch we can lower the default quantum, and the output is like this: ``` $ RUBY_THREAD_DEFAULT_QUANTUM_MS=10 ./miniruby -v fibtest.rb ruby 3.4.0dev (2024-11-01T22:06:35Z quantum-computing 087500643d) +PRISM [arm64-darwin24] done 2 done 1 {TOTAL: 8.898526000091806, WASTE: 1.4168260043952614} ``` Specifying the ENV to change the quantum to 10ms lowered our waste in the program to ~1.4 seconds. It's common for web applications to do mixed CPU and IO bound tasks in threads (see the Puma webserver), so it would be great if there was a way to customize the thread quantum depending on your application's workload. -- https://bugs.ruby-lang.org/

11 23

[ruby-core:115981] [Ruby master Bug#20105] Introduce `IO::Stream` or something similar.
by ioquatix (Samuel Williams) 07 Jun '25

07 Jun '25

Issue #20105 has been reported by ioquatix (Samuel Williams). ---------------------------------------- Bug #20105: Introduce `IO::Stream` or something similar. https://bugs.ruby-lang.org/issues/20105 * Author: ioquatix (Samuel Williams) * Status: Open * Priority: Normal * Assignee: ioquatix (Samuel Williams) * Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- Ruby's IO class has a general model for streaming IO, including some hidden classes like `IO::generic_readable` and `IO::generic_writable`. As Ruby's core IO classes evolve, gems like `openssl` (see `OpenSSL::Buffering`) need to be updated to support changes to the interface. As it stands, there are changes in `IO` which are not copied to `OpenSSL::Buffering`. I'd like to propose we introduce some shared interface for streams that is used by `IO`, `Socket`, and `OpenSSL` to start with. The general interface would be similar to `IO` and allow code like `OpenSSL` to avoid re-implementing the `IO` interface. -- https://bugs.ruby-lang.org/

2 2

[ruby-core:119991] [Ruby master Bug#20905] Ruby VM hangs while using ractors
by ivoanjo (Ivo Anjo) 05 Jun '25

05 Jun '25

Issue #20905 has been reported by ivoanjo (Ivo Anjo). ---------------------------------------- Bug #20905: Ruby VM hangs while using ractors https://bugs.ruby-lang.org/issues/20905 * Author: ivoanjo (Ivo Anjo) * Status: Open * ruby -v: ruby 3.4.0preview2 (2024-10-07 master 32c733f57b) +PRISM [x86_64-linux] * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- Hey! While doing some experiments with Ractors I ran into a Ruby VM hang. I see it both on Ruby 3.4.0-preview2 and 3.3.5, but not Ruby 3.2, so this may be related to the M:N scheduling. ### How to reproduce: ``` puts RUBY_DESCRIPTION def counter_loop counter = 0 counter += 1 while counter < 100_000_000 end ractors = 10.times.map { Ractor.new { Thread.new { counter_loop }; counter_loop } } counter_loop ractors.map(&:take) ``` This example never finishes for me. At some point all threads finish work, and the Ruby process will be stuck at 0% cpu. ``` ruby 3.4.0preview2 (2024-10-07 master 32c733f57b) +PRISM [x86_64-linux] warning: Ractor is experimental, and the behavior may change in future versions of Ruby! Also there are many implementation issues. ...(hangs)... ``` Reducing the number of ractor seems to make the issue go away, so there may be some timing/thread switching issues involved. Furthermore, all threads seem to be stuck waiting: ``` (gdb) info threads Id Target Id Frame * 1 Thread 0x7836ef0b6c00 (LWP 445418) "ruby" __futex_abstimed_wait_common64 (private=0, cancel=true, abstime=0x0, op=393, expected=0, futex_word=0x59a4024bda30) at ./nptl/futex-internal.c:57 2 Thread 0x7836d4800640 (LWP 445419) "ruby" 0x00007836ee725e2e in epoll_wait (epfd=4, events=events@entry=0x7836ef0a8adc <timer_th+28>, maxevents=maxevents@entry=16, timeout=timeout@entry=-1) at ../sysdeps/unix/sysv/linux/epoll_wait.c:30 3 Thread 0x7836d3fff640 (LWP 445420) "rc-example7-2.*" __futex_abstimed_wait_common64 (private=0, cancel=true, abstime=0x0, op=393, expected=0, futex_word=0x59a4024b6434) at ./nptl/futex-internal.c:57 4 Thread 0x7836b29ff640 (LWP 445421) "rc-example7-2.*" __futex_abstimed_wait_common64 (private=0, cancel=true, abstime=0x0, op=393, expected=0, futex_word=0x59a4024b6434) at ./nptl/futex-internal.c:57 5 Thread 0x7836b28fe640 (LWP 445422) "rc-example7-2.*" __futex_abstimed_wait_common64 (private=0, cancel=true, abstime=0x0, op=393, expected=0, futex_word=0x59a4024b6430) at ./nptl/futex-internal.c:57 6 Thread 0x7836b27fd640 (LWP 445423) "rc-example7-2.*" __futex_abstimed_wait_common64 (private=0, cancel=true, abstime=0x0, op=393, expected=0, futex_word=0x59a4024b6430) at ./nptl/futex-internal.c:57 7 Thread 0x7836b26fc640 (LWP 445424) "rc-example7-2.*" __futex_abstimed_wait_common64 (private=0, cancel=true, abstime=0x0, op=393, expected=0, futex_word=0x59a4024b6430) at ./nptl/futex-internal.c:57 8 Thread 0x7836b25fb640 (LWP 445425) "rc-example7-2.*" __futex_abstimed_wait_common64 (private=0, cancel=true, abstime=0x0, op=393, expected=0, futex_word=0x59a4024b6430) at ./nptl/futex-internal.c:57 9 Thread 0x7836b24fa640 (LWP 445426) "rc-example7-2.*" __futex_abstimed_wait_common64 (private=0, cancel=true, abstime=0x0, op=393, expected=0, futex_word=0x59a4024b6430) at ./nptl/futex-internal.c:57 (gdb) thread apply all bt Thread 9 (Thread 0x7836b24fa640 (LWP 445426) "rc-example7-2.*"): #0 __futex_abstimed_wait_common64 (private=0, cancel=true, abstime=0x0, op=393, expected=0, futex_word=0x59a4024b6430) at ./nptl/futex-internal.c:57 #1 __futex_abstimed_wait_common (cancel=true, private=0, abstime=0x0, clockid=0, expected=0, futex_word=0x59a4024b6430) at ./nptl/futex-internal.c:87 #2 __GI___futex_abstimed_wait_cancelable64 (futex_word=futex_word@entry=0x59a4024b6430, expected=expected@entry=0, clockid=clockid@entry=0, abstime=abstime@entry=0x0, private=private@entry=0) at ./nptl/futex-internal.c:139 #3 0x00007836ee693a41 in __pthread_cond_wait_common (abstime=0x0, clockid=0, mutex=0x59a4024b63d0, cond=0x59a4024b6408) at ./nptl/pthread_cond_wait.c:503 #4 ___pthread_cond_wait (cond=cond@entry=0x59a4024b6408, mutex=mutex@entry=0x59a4024b63d0) at ./nptl/pthread_cond_wait.c:627 #5 0x00007836eecd77dd in rb_native_cond_wait (cond=cond@entry=0x59a4024b6408, mutex=mutex@entry=0x59a4024b63d0) at src/ruby-3.4.0-preview2/thread_pthread.c:222 #6 0x00007836eece2e53 in ractor_sched_deq (cr=0x0, vm=0x59a4024b6330) at src/ruby-3.4.0-preview2/thread_pthread.c:1292 #7 nt_start (ptr=0x59a40251e800) at src/ruby-3.4.0-preview2/thread_pthread.c:2287 #8 0x00007836ee694ac3 in start_thread (arg=<optimised out>) at ./nptl/pthread_create.c:442 #9 0x00007836ee726850 in clone3 () at ../sysdeps/unix/sysv/linux/x86_64/clone3.S:81 Thread 8 (Thread 0x7836b25fb640 (LWP 445425) "rc-example7-2.*"): #0 __futex_abstimed_wait_common64 (private=0, cancel=true, abstime=0x0, op=393, expected=0, futex_word=0x59a4024b6430) at ./nptl/futex-internal.c:57 #1 __futex_abstimed_wait_common (cancel=true, private=0, abstime=0x0, clockid=0, expected=0, futex_word=0x59a4024b6430) at ./nptl/futex-internal.c:87 #2 __GI___futex_abstimed_wait_cancelable64 (futex_word=futex_word@entry=0x59a4024b6430, expected=expected@entry=0, clockid=clockid@entry=0, abstime=abstime@entry=0x0, private=private@entry=0) at ./nptl/futex-internal.c:139 #3 0x00007836ee693a41 in __pthread_cond_wait_common (abstime=0x0, clockid=0, mutex=0x59a4024b63d0, cond=0x59a4024b6408) at ./nptl/pthread_cond_wait.c:503 #4 ___pthread_cond_wait (cond=cond@entry=0x59a4024b6408, mutex=mutex@entry=0x59a4024b63d0) at ./nptl/pthread_cond_wait.c:627 #5 0x00007836eecd77dd in rb_native_cond_wait (cond=cond@entry=0x59a4024b6408, mutex=mutex@entry=0x59a4024b63d0) at src/ruby-3.4.0-preview2/thread_pthread.c:222 #6 0x00007836eece2e53 in ractor_sched_deq (cr=0x0, vm=0x59a4024b6330) at src/ruby-3.4.0-preview2/thread_pthread.c:1292 #7 nt_start (ptr=0x59a4025224e0) at src/ruby-3.4.0-preview2/thread_pthread.c:2287 #8 0x00007836ee694ac3 in start_thread (arg=<optimised out>) at ./nptl/pthread_create.c:442 #9 0x00007836ee726850 in clone3 () at ../sysdeps/unix/sysv/linux/x86_64/clone3.S:81 Thread 7 (Thread 0x7836b26fc640 (LWP 445424) "rc-example7-2.*"): #0 __futex_abstimed_wait_common64 (private=0, cancel=true, abstime=0x0, op=393, expected=0, futex_word=0x59a4024b6430) at ./nptl/futex-internal.c:57 #1 __futex_abstimed_wait_common (cancel=true, private=0, abstime=0x0, clockid=0, expected=0, futex_word=0x59a4024b6430) at ./nptl/futex-internal.c:87 #2 __GI___futex_abstimed_wait_cancelable64 (futex_word=futex_word@entry=0x59a4024b6430, expected=expected@entry=0, clockid=clockid@entry=0, abstime=abstime@entry=0x0, private=private@entry=0) at ./nptl/futex-internal.c:139 #3 0x00007836ee693a41 in __pthread_cond_wait_common (abstime=0x0, clockid=0, mutex=0x59a4024b63d0, cond=0x59a4024b6408) at ./nptl/pthread_cond_wait.c:503 #4 ___pthread_cond_wait (cond=cond@entry=0x59a4024b6408, mutex=mutex@entry=0x59a4024b63d0) at ./nptl/pthread_cond_wait.c:627 #5 0x00007836eecd77dd in rb_native_cond_wait (cond=cond@entry=0x59a4024b6408, mutex=mutex@entry=0x59a4024b63d0) at src/ruby-3.4.0-preview2/thread_pthread.c:222 #6 0x00007836eece2e53 in ractor_sched_deq (cr=0x0, vm=0x59a4024b6330) at src/ruby-3.4.0-preview2/thread_pthread.c:1292 #7 nt_start (ptr=0x59a4025adf00) at src/ruby-3.4.0-preview2/thread_pthread.c:2287 #8 0x00007836ee694ac3 in start_thread (arg=<optimised out>) at ./nptl/pthread_create.c:442 #9 0x00007836ee726850 in clone3 () at ../sysdeps/unix/sysv/linux/x86_64/clone3.S:81 Thread 6 (Thread 0x7836b27fd640 (LWP 445423) "rc-example7-2.*"): #0 __futex_abstimed_wait_common64 (private=0, cancel=true, abstime=0x0, op=393, expected=0, futex_word=0x59a4024b6430) at ./nptl/futex-internal.c:57 #1 __futex_abstimed_wait_common (cancel=true, private=0, abstime=0x0, clockid=0, expected=0, futex_word=0x59a4024b6430) at ./nptl/futex-internal.c:87 #2 __GI___futex_abstimed_wait_cancelable64 (futex_word=futex_word@entry=0x59a4024b6430, expected=expected@entry=0, clockid=clockid@entry=0, abstime=abstime@entry=0x0, private=private@entry=0) at ./nptl/futex-internal.c:139 #3 0x00007836ee693a41 in __pthread_cond_wait_common (abstime=0x0, clockid=0, mutex=0x59a4024b63d0, cond=0x59a4024b6408) at ./nptl/pthread_cond_wait.c:503 #4 ___pthread_cond_wait (cond=cond@entry=0x59a4024b6408, mutex=mutex@entry=0x59a4024b63d0) at ./nptl/pthread_cond_wait.c:627 #5 0x00007836eecd77dd in rb_native_cond_wait (cond=cond@entry=0x59a4024b6408, mutex=mutex@entry=0x59a4024b63d0) at src/ruby-3.4.0-preview2/thread_pthread.c:222 #6 0x00007836eece2e53 in ractor_sched_deq (cr=0x0, vm=0x59a4024b6330) at src/ruby-3.4.0-preview2/thread_pthread.c:1292 #7 nt_start (ptr=0x59a40263bc20) at src/ruby-3.4.0-preview2/thread_pthread.c:2287 #8 0x00007836ee694ac3 in start_thread (arg=<optimised out>) at ./nptl/pthread_create.c:442 #9 0x00007836ee726850 in clone3 () at ../sysdeps/unix/sysv/linux/x86_64/clone3.S:81 Thread 5 (Thread 0x7836b28fe640 (LWP 445422) "rc-example7-2.*"): #0 __futex_abstimed_wait_common64 (private=0, cancel=true, abstime=0x0, op=393, expected=0, futex_word=0x59a4024b6430) at ./nptl/futex-internal.c:57 #1 __futex_abstimed_wait_common (cancel=true, private=0, abstime=0x0, clockid=0, expected=0, futex_word=0x59a4024b6430) at ./nptl/futex-internal.c:87 #2 __GI___futex_abstimed_wait_cancelable64 (futex_word=futex_word@entry=0x59a4024b6430, expected=expected@entry=0, clockid=clockid@entry=0, abstime=abstime@entry=0x0, private=private@entry=0) at ./nptl/futex-internal.c:139 #3 0x00007836ee693a41 in __pthread_cond_wait_common (abstime=0x0, clockid=0, mutex=0x59a4024b63d0, cond=0x59a4024b6408) at ./nptl/pthread_cond_wait.c:503 #4 ___pthread_cond_wait (cond=cond@entry=0x59a4024b6408, mutex=mutex@entry=0x59a4024b63d0) at ./nptl/pthread_cond_wait.c:627 #5 0x00007836eecd77dd in rb_native_cond_wait (cond=cond@entry=0x59a4024b6408, mutex=mutex@entry=0x59a4024b63d0) at src/ruby-3.4.0-preview2/thread_pthread.c:222 #6 0x00007836eece2e53 in ractor_sched_deq (cr=0x0, vm=0x59a4024b6330) at src/ruby-3.4.0-preview2/thread_pthread.c:1292 #7 nt_start (ptr=0x59a40276bc80) at src/ruby-3.4.0-preview2/thread_pthread.c:2287 #8 0x00007836ee694ac3 in start_thread (arg=<optimised out>) at ./nptl/pthread_create.c:442 #9 0x00007836ee726850 in clone3 () at ../sysdeps/unix/sysv/linux/x86_64/clone3.S:81 Thread 4 (Thread 0x7836b29ff640 (LWP 445421) "rc-example7-2.*"): #0 __futex_abstimed_wait_common64 (private=0, cancel=true, abstime=0x0, op=393, expected=0, futex_word=0x59a4024b6434) at ./nptl/futex-internal.c:57 #1 __futex_abstimed_wait_common (cancel=true, private=0, abstime=0x0, clockid=0, expected=0, futex_word=0x59a4024b6434) at ./nptl/futex-internal.c:87 #2 __GI___futex_abstimed_wait_cancelable64 (futex_word=futex_word@entry=0x59a4024b6434, expected=expected@entry=0, clockid=clockid@entry=0, abstime=abstime@entry=0x0, private=private@entry=0) at ./nptl/futex-internal.c:139 #3 0x00007836ee693a41 in __pthread_cond_wait_common (abstime=0x0, clockid=0, mutex=0x59a4024b63d0, cond=0x59a4024b6408) at ./nptl/pthread_cond_wait.c:503 #4 ___pthread_cond_wait (cond=cond@entry=0x59a4024b6408, mutex=mutex@entry=0x59a4024b63d0) at ./nptl/pthread_cond_wait.c:627 #5 0x00007836eecd77dd in rb_native_cond_wait (cond=cond@entry=0x59a4024b6408, mutex=mutex@entry=0x59a4024b63d0) at src/ruby-3.4.0-preview2/thread_pthread.c:222 #6 0x00007836eece2e53 in ractor_sched_deq (cr=0x0, vm=0x59a4024b6330) at src/ruby-3.4.0-preview2/thread_pthread.c:1292 #7 nt_start (ptr=0x59a402729730) at src/ruby-3.4.0-preview2/thread_pthread.c:2287 #8 0x00007836ee694ac3 in start_thread (arg=<optimised out>) at ./nptl/pthread_create.c:442 #9 0x00007836ee726850 in clone3 () at ../sysdeps/unix/sysv/linux/x86_64/clone3.S:81 Thread 3 (Thread 0x7836d3fff640 (LWP 445420) "rc-example7-2.*"): #0 __futex_abstimed_wait_common64 (private=0, cancel=true, abstime=0x0, op=393, expected=0, futex_word=0x59a4024b6434) at ./nptl/futex-internal.c:57 #1 __futex_abstimed_wait_common (cancel=true, private=0, abstime=0x0, clockid=0, expected=0, futex_word=0x59a4024b6434) at ./nptl/futex-internal.c:87 #2 __GI___futex_abstimed_wait_cancelable64 (futex_word=futex_word@entry=0x59a4024b6434, expected=expected@entry=0, clockid=clockid@entry=0, abstime=abstime@entry=0x0, private=private@entry=0) at ./nptl/futex-internal.c:139 #3 0x00007836ee693a41 in __pthread_cond_wait_common (abstime=0x0, clockid=0, mutex=0x59a4024b63d0, cond=0x59a4024b6408) at ./nptl/pthread_cond_wait.c:503 #4 ___pthread_cond_wait (cond=cond@entry=0x59a4024b6408, mutex=mutex@entry=0x59a4024b63d0) at ./nptl/pthread_cond_wait.c:627 #5 0x00007836eecd77dd in rb_native_cond_wait (cond=cond@entry=0x59a4024b6408, mutex=mutex@entry=0x59a4024b63d0) at src/ruby-3.4.0-preview2/thread_pthread.c:222 #6 0x00007836eece2e53 in ractor_sched_deq (cr=0x0, vm=0x59a4024b6330) at src/ruby-3.4.0-preview2/thread_pthread.c:1292 #7 nt_start (ptr=0x59a4024bb430) at src/ruby-3.4.0-preview2/thread_pthread.c:2287 #8 0x00007836ee694ac3 in start_thread (arg=<optimised out>) at ./nptl/pthread_create.c:442 #9 0x00007836ee726850 in clone3 () at ../sysdeps/unix/sysv/linux/x86_64/clone3.S:81 Thread 2 (Thread 0x7836d4800640 (LWP 445419) "ruby"): #0 0x00007836ee725e2e in epoll_wait (epfd=4, events=events@entry=0x7836ef0a8adc <timer_th+28>, maxevents=maxevents@entry=16, timeout=timeout@entry=-1) at ../sysdeps/unix/sysv/linux/epoll_wait.c:30 #1 0x00007836eecdca8d in event_wait (vm=0x59a4024b6330) at src/ruby-3.4.0-preview2/thread_pthread.c:2940 #2 timer_thread_polling (vm=0x59a4024b6330) at src/ruby-3.4.0-preview2/thread_pthread_mn.c:908 #3 timer_thread_func (ptr=0x59a4024b6330) at src/ruby-3.4.0-preview2/thread_pthread.c:3067 #4 0x00007836ee694ac3 in start_thread (arg=<optimised out>) at ./nptl/pthread_create.c:442 #5 0x00007836ee726850 in clone3 () at ../sysdeps/unix/sysv/linux/x86_64/clone3.S:81 Thread 1 (Thread 0x7836ef0b6c00 (LWP 445418) "ruby"): #0 __futex_abstimed_wait_common64 (private=0, cancel=true, abstime=0x0, op=393, expected=0, futex_word=0x59a4024bda30) at ./nptl/futex-internal.c:57 #1 __futex_abstimed_wait_common (cancel=true, private=0, abstime=0x0, clockid=0, expected=0, futex_word=0x59a4024bda30) at ./nptl/futex-internal.c:87 #2 __GI___futex_abstimed_wait_cancelable64 (futex_word=futex_word@entry=0x59a4024bda30, expected=expected@entry=0, clockid=clockid@entry=0, abstime=abstime@entry=0x0, private=private@entry=0) at ./nptl/futex-internal.c:139 #3 0x00007836ee693a41 in __pthread_cond_wait_common (abstime=0x0, clockid=0, mutex=0x59a4024bdb80, cond=0x59a4024bda08) at ./nptl/pthread_cond_wait.c:503 #4 ___pthread_cond_wait (cond=cond@entry=0x59a4024bda08, mutex=mutex@entry=0x59a4024bdb80) at ./nptl/pthread_cond_wait.c:627 #5 0x00007836eecd77dd in rb_native_cond_wait (cond=cond@entry=0x59a4024bda08, mutex=mutex@entry=0x59a4024bdb80) at src/ruby-3.4.0-preview2/thread_pthread.c:222 #6 0x00007836eecd90d9 in thread_sched_wait_running_turn (sched=sched@entry=0x59a4024bdb80, th=0x59a4024b88c0, can_direct_transfer=can_direct_transfer@entry=false) at src/ruby-3.4.0-preview2/thread_pthread.c:863 #7 0x00007836eecd9f4a in rb_ractor_sched_sleep (ec=ec@entry=0x59a4024bdd20, cr=cr@entry=0x59a4024bda60, ubf=ubf@entry=0x7836eec341f0 <ractor_sleep_interrupt>) at src/ruby-3.4.0-preview2/thread_pthread.c:1349 #8 0x00007836eec34de6 in ractor_sleep_with_cleanup (cf_data=0x7ffcaa1e7640, cf_func=0x7836eec35b70 <ractor_wait_take_cleanup>, wait_status=wait_taking, cr=0x59a4024bda60, ec=0x59a4024bdd20) at ractor.c:691 #9 ractor_wait_take (take_basket=0x7ffcaa1e7650, r=0x59a4027851d0, cr=0x59a4024bda60, ec=0x59a4024bdd20) at ractor.c:1220 #10 ractor_take (r=0x59a4027851d0, ec=0x59a4024bdd20) at ractor.c:1241 #11 builtin_inline_class_711 (ec=0x59a4024bdd20, self=<optimised out>) at src/ruby-3.4.0-preview2/ractor.rb:712 #12 0x00007836eed30fe7 in invoke_bf (argv=<optimised out>, bf=<optimised out>, reg_cfp=<optimised out>, ec=<optimised out>) at src/ruby-3.4.0-preview2/vm_insnhelper.c:7330 #13 vm_invoke_builtin_delegate (cfp=<optimised out>, bf=<optimised out>, cfp=<optimised out>, bf=<optimised out>, start_index=<optimised out>, ec=<optimised out>) at src/ruby-3.4.0-preview2/vm_insnhelper.c:7353 #14 vm_invoke_builtin_delegate (start_index=<optimised out>, bf=<optimised out>, cfp=<optimised out>, ec=<optimised out>) at src/ruby-3.4.0-preview2/vm_insnhelper.c:7342 #15 vm_exec_core (ec=0x59a4024bdd20) at src/ruby-3.4.0-preview2/insns.def:1632 #16 0x00007836eed34c1a in rb_vm_exec (ec=0x59a4024bdd20) at vm.c:2564 #17 0x00007836eed3b222 in vm_call0_cc (ec=0x59a4024bdd20, recv=132176890167200, id=<optimised out>, argc=<optimised out>, argv=<optimised out>, cc=<optimised out>, kw_splat=0) at src/ruby-3.4.0-preview2/vm_eval.c:101 #18 0x00007836eed3d9e4 in rb_call0 (ec=0x59a4024bdd20, recv=132176890167200, mid=6081, argc=0, argv=<optimised out>, call_scope=<optimised out>, self=132177315121880) at src/ruby-3.4.0-preview2/vm_eval.c:554 #19 0x00007836eed3e6f6 in rb_call (scope=<optimised out>, argv=0x7ffcaa1e7b40, argc=0, mid=6081, recv=132176890167200) at src/ruby-3.4.0-preview2/vm_eval.c:873 #20 rb_funcall_with_block_kw (recv=132176890167200, mid=6081, argc=0, argv=0x7ffcaa1e7b40, passed_procval=4, kw_splat=<optimised out>) at src/ruby-3.4.0-preview2/vm_eval.c:1192 #21 0x00007836eed39e38 in vm_yield_with_cref (is_lambda=0, cref=0x0, kw_splat=0, argv=0x7ffcaa1e7b38, argc=1, ec=<optimised out>) at vm.c:1646 #22 vm_yield (kw_splat=0, argv=0x7ffcaa1e7b38, argc=1, ec=<optimised out>) at vm.c:1654 #23 rb_yield_0 (argv=0x7ffcaa1e7b38, argc=1) at src/ruby-3.4.0-preview2/vm_eval.c:1344 #24 rb_yield (val=<optimised out>) at src/ruby-3.4.0-preview2/vm_eval.c:1360 #25 0x00007836eea68efc in rb_ary_collect (ary=132177315121880) at array.c:3714 #26 0x00007836eed1b03c in vm_call_cfunc_with_frame_ (stack_bottom=<optimised out>, argv=<optimised out>, argc=0, calling=<optimised out>, reg_cfp=0x7836edffefa0, ec=0x59a4024bdd20) at src/ruby-3.4.0-preview2/vm_insnhelper.c:3788 #27 vm_call_cfunc_with_frame (ec=0x59a4024bdd20, reg_cfp=0x7836edffefa0, calling=<optimised out>) at src/ruby-3.4.0-preview2/vm_insnhelper.c:3834 #28 0x00007836eed217f0 in vm_sendish (ec=0x59a4024bdd20, reg_cfp=0x7836edffefa0, cd=0x59a4027833f0, block_handler=<optimised out>, method_explorer=mexp_search_method) at src/ruby-3.4.0-preview2/vm_callinfo.h:415 #29 0x00007836eed2edd1 in vm_exec_core (ec=0x59a4024bdd20) at src/ruby-3.4.0-preview2/insns.def:851 #30 0x00007836eed34c1a in rb_vm_exec (ec=0x59a4024bdd20) at vm.c:2564 #31 0x00007836eed46e8b in rb_iseq_eval_main (iseq=iseq@entry=0x7836edea70f8) at vm.c:2830 #32 0x00007836eeb3d895 in rb_ec_exec_node (ec=ec@entry=0x59a4024bdd20, n=n@entry=0x7836edea70f8) at eval.c:281 #33 0x00007836eeb4140b in ruby_run_node (n=0x7836edea70f8) at eval.c:319 #34 0x000059a400cd1187 in rb_main (argv=0x7ffcaa1e8118, argc=2) at ./main.c:43 #35 main (argc=<optimised out>, argv=<optimised out>) at ./main.c:62 ``` -- https://bugs.ruby-lang.org/

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[ruby-core:119645] [Ruby master Bug#20854] Some bundled gems are not installed starting with 007c75ce4c66243e41144c6977e5ccbf4ab71c93
by jvreeland (Justin Vreeland) 04 Jun '25

04 Jun '25

Issue #20854 has been reported by jvreeland (Justin Vreeland). ---------------------------------------- Bug #20854: Some bundled gems are not installed starting with 007c75ce4c66243e41144c6977e5ccbf4ab71c93 https://bugs.ruby-lang.org/issues/20854 * Author: jvreeland (Justin Vreeland) * Status: Open * ruby -v: Building ruby from master * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- I noticed in ruby 3.4.0 preview 2 that some bundled gems weren't being installed any more. I'm running in the same environment each time and bundled gems are installed fine with 3.3 or with the mentioned commit reverted. I bisected this from a version that did install the gems to 007c75ce4c66243e41144c6977e5ccbf4ab71c93 . The comment in that commit does indicate that it's mean to skip games if the gems are not found or can't be built but the final message is 'not found in bundled_gems'. I'm unsure if this is this is working as intended. When my build finishes I see the following line in the log: ``` installing bundled gem cache: /home/user/ruby/build/.rubies/bisect/lib/ruby/gems/3.4.0+0/cache skipped bundled gems: bigdecimal-3.1.8.gem not found in bundled_gems debug-1.9.2.gem not found in bundled_gems nkf-0.2.0.gem not found in bundled_gems/rac racc-1.8.1.gem not found in bundled_gems rbs-3.6.1.gem not found in bundled_gems syslog-0.1.2.gem not found in bundled_gems typeprof-0.30.0.gem not found in bundled_gems ``` I see racc in bundled gems and cached in downloads. I don't see any files named gem.build_complete or errors concerning gem building or missing C extensions in my build logs. Is there additional configure flags or dependencies I need to include the bundled gems in the upcoming 3.4.0 ruby release? I followed the instructions at: https://docs.ruby-lang.org/en/master/contributing/building_ruby_md.html to build: ``` git clean -dxf git checkout -f autoreconf -fi mkdir build pushd build ../configure --prefix=(pwd)/.rubies/bisect make -j(nproc) make install popd find build/.rubies/bisect -name 'racc' | grep . ``` -- https://bugs.ruby-lang.org/

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[ruby-core:118191] [Ruby master Bug#20560] make install - skipped bundled gems - minor issue
by MSP-Greg (Greg L) 04 Jun '25

04 Jun '25

Issue #20560 has been reported by MSP-Greg (Greg L). ---------------------------------------- Bug #20560: make install - skipped bundled gems - minor issue https://bugs.ruby-lang.org/issues/20560 * Author: MSP-Greg (Greg L) * Status: Open * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- See most recent job: https://github.com/ruby/ruby/actions/runs/9389674968/job/25857719333#step:9… Which is logging the following during `make install`: ``` skipped bundled gems: power_assert-2.0.4dev.gem not found in bundled_gems syslog-0.1.2.gem not found in bundled_gems ``` Not sure what the correct versioning should be. Or, should bundled gems use 'dev' versions, etc... -- https://bugs.ruby-lang.org/

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[ruby-core:115995] [Ruby master Bug#20112] Ractors not working properly in ruby 3.3.0
by ariasdiniz (Aria Diniz) 19 May '25

19 May '25

Issue #20112 has been reported by ariasdiniz (Aria Diniz). ---------------------------------------- Bug #20112: Ractors not working properly in ruby 3.3.0 https://bugs.ruby-lang.org/issues/20112 * Author: ariasdiniz (Aria Diniz) * Status: Open * Priority: Normal * ruby -v: 3.3.0 * Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- I recently installed Ruby 3.3.0, and noticed that some of my scripts that use Ractors started to struggle with performance. After doing some benchmarks, I noticed that, while Ractors seem to be working well on Ruby 3.2.2, they're not working properly on 3.3.0. I'm using Ubuntu 22.04.3 LTS Here is the benchmark code: ``` ruby # frozen_string_literal: true require 'benchmark' Ractor.new { :warmup } if defined?(Ractor) Benchmark.bmbm do |x| x.report("Thread: ") do threads = [] 8.times do |i| threads << Thread.new do 20000000.times do |j| ((i * 20000000) + j)**2 end end end threads.each(&:join) end x.report("Ractor: ") do ractors = [] 0..8.times do |i| ractors << Ractor.new(i) do |k| 20000000.times do |j| ((k * 20000000) + j)**2 end end end ractors.map(&:take) end end ``` Here is the results for Ruby 3.2.2: Rehearsal -------------------------------------------- Thread: 7.666909 0.001091 7.668000 ( 7.675266) Ractor: 19.318528 0.012017 19.330545 ( 2.505888) ---------------------------------- total: 26.998545sec user system total real Thread: 7.918141 0.004011 7.922152 ( 7.928772) Ractor: 19.366414 0.003954 19.370368 ( 2.517993) Here is the results for Ruby 3.3.0: Rehearsal -------------------------------------------- Thread: 8.634152 0.010895 8.645047 ( 8.645104) Ractor: 100.172179 0.035985 100.208164 ( 15.213245) --------------------------------- total: 108.853211sec user system total real Thread: 9.451236 0.004002 9.455238 ( 9.460132) Ractor: 118.463294 0.119942 118.583236 ( 18.462157) -- https://bugs.ruby-lang.org/

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[ruby-core:119137] [Ruby master Bug#20726] Issue with hash without braces when assigned to constant with ractor literals
by luke-gru (Luke Gruber) 14 May '25

14 May '25

Issue #20726 has been reported by luke-gru (Luke Gruber). ---------------------------------------- Bug #20726: Issue with hash without braces when assigned to constant with ractor literals https://bugs.ruby-lang.org/issues/20726 * Author: luke-gru (Luke Gruber) * Status: Open * ruby -v: 3.4.0dev * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- ```ruby a = 'hi' A = ['hello' => a] p A ``` gives: ``` ./ruby -I../ruby/lib -I. -I.ext/x86_64-linux -I.ext/common -r./x86_64-linux-fake ../ruby/test.rb -- raw disasm-------- trace: 1 0000 putchilledstring "hi" ( 3) 0002 setlocal_WC_0 3 ( 3) trace: 1 0004 newarray 1 ( 4) 0006 putspecialobject 3 ( 4) * 0008 setconstant :A ( 4) trace: 1 0010 putself ( 5) 0011 opt_getconstant_path [:A] ( 5) 0013 opt_send_without_block <calldata:p, 1> ( 5) 0015 leave ( 5) --------------------- ../ruby/test.rb:4: argument stack underflow (-1) ../ruby/test.rb: compile error (SyntaxError) ``` This is due to a line in `compile.c`, function `compile_shareable_literal_constant`: ```c if (!RNODE_HASH(node)->nd_brace) { } ``` I'm not sure why this condition is there so I'm not confident in making a fix. Also, my git-fu isn't the best so I can't track down the right commit where it was added. -- https://bugs.ruby-lang.org/

4 3

[ruby-core:111809] [Ruby master Bug#19338] Ruby hangs when defining new constant in ractor
by luke-gru (Luke Gruber) 13 May '25

13 May '25

Issue #19338 has been reported by luke-gru (Luke Gruber). ---------------------------------------- Bug #19338: Ruby hangs when defining new constant in ractor https://bugs.ruby-lang.org/issues/19338 * Author: luke-gru (Luke Gruber) * Status: Open * Priority: Normal * Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN ---------------------------------------- This code causes Ruby to hang: ``` ruby rs = [] 2.times do rs << Ractor.new do MYCONSTANT = 2 end end rs.each(&:take) ``` There is a problem when the warning is being outputted with multiple ractors. A thread is calling RB_VM_LOCK() while holding the VM lock in ractor.c (ractor_check_blocking()) If the code is changed to RB_VM_LOCK_ENTER() and RB_VM_LOCK_LEAVE() then it fixes it, but I don't know if there's a better way. Thanks! -- https://bugs.ruby-lang.org/

3 3

[ruby-core:118467] [Ruby master Feature#20610] Float::INFINITY as IO.select timeout argument
by akr (Akira Tanaka) 13 May '25

13 May '25

Issue #20610 has been reported by akr (Akira Tanaka). ---------------------------------------- Feature #20610: Float::INFINITY as IO.select timeout argument https://bugs.ruby-lang.org/issues/20610 * Author: akr (Akira Tanaka) * Status: Open ---------------------------------------- I propose IO.select accepts Float::INFINITY as a timeout argument. It behaves the same as nil which means IO.select will block indefinitely. Motivation: Currently, the Ruby convention to indicate no timeout is using nil. This practice often forces us to treat the nil case separately. Conceptually, no timeout can be thought of as an infinite timeout. So I propose to accept Float::INFINITY as a timeout. It makes us less conditionals when we need to calculate or compare timeouts. Assume `now` method as follows to read the following examples. ``` def now = Process.clock_gettime(Process::CLOCK_MONOTONIC) ``` Example 1: absolute timeout Sometimes we maintain timeout as an absolute clock. The following method takes a relative timeout as an argument. It invokes IO.select several times and raises if the timeout is reached. Assuming a user must specify a finite timeout, the following definition is possible. ``` # user_timeout is the required argument def method(..., user_timeout) abs_timeout = now + user_timeout loop { IO.select(rs, ws, es, (abs_timeout - now).clamp(0..)) raise "timeout" if abs_timeout < now ... } end ``` Consider we need to make user_timeout optional. If user_timeout is not given, no timeout occurs. The implementation is as follows. I think the following implementation is typical. It needs 3 more conditionals than the above. ``` # user_timeout is an optional argument. nil means no timeout. def method(..., user_timeout=nil) abs_timeout = user_timeout ? now + user_timeout : nil loop { IO.select(rs, ws, es, user_timeout ? (abs_timeout - now).clamp(0..) : nil) raise "timeout" if abs_timeout && (abs_timeout < now) ... } end ``` It is possible to reduce a conditional if we use Float::INFINITY. (`abs_timeout && (abs_timeout < now)` is changed to `abs_timeout < now`) ``` # user_timeout is an optional argument. nil means no timeout. def method(..., user_timeout=nil) abs_timeout = user_timeout ? now + user_timeout : Float::INFINITY loop { IO.select(rs, ws, es, abs_timeout != Float::INFINITY ? (abs_timeout - now).clamp(0..) : nil) raise "timeout" if abs_timeout < now ... } end ``` If IO.select accepts Float::INFINITY as a timeout argument (this proposal), we can reduce one more conditional as follows. ``` # user_timeout is an optional argument. nil means no timeout. def method(..., user_timeout=nil) abs_timeout = user_timeout ? now + user_timeout : Float::INFINITY loop { IO.select(rs, ws, es, (abs_timeout - now).clamp(0..)) raise "timeout" if abs_timeout < now ... } end ``` Example 2: minimum of timeouts Sometimes we need to choose the minimum of several timeouts. I think many event-driven programs use this strategy to determine the timeout for select function. If "no timeout" is represented as nil, `[t1, t2, t3, ...].compact.min` is the minimum. If "no timeout" is represented as Float::INFINITY, we can remove `compact`: `[t1, t2, t3, ...].min` However, Float::INFINITY must be converted to nil for IO.select. This proposal removes this conversion. Example 3: maximum of timeouts Sometimes we need to choose the maximum of several timeouts. We encountered this situation with a Happy Eyeballs implementation. There are two timeouts for getaddrinfo and connect. We need to wait the longer timeout because a timeout for one doesn't stop another. Also, we don't ignore results after a timeout as long as the algorithm waits for something. If "no timeout" is represented as nil, `ts = [t1, t2, t3, ...]; ts.include?(nil) ? nil : ts.max` is the maximum. If "no timeout" is represented as Float::INFINITY, we can compute the maximum more easily: `[t1, t2, t3, ...].max` It makes code simpler. However, Float::INFINITY must be converted to nil for IO.select. This proposal removes this conversion. Several Consideration: Consideration 1: Methods other than IO.select. Several methods take a timeout. An incomplete list of methods is as follows. (I searched rb_time_interval.) - IO.select(rs, ws, es, timeout) - sleep(secs) - TCPSocket.new(connect_timeout:) - io.wait_readable(timeout) - io.wait_writable(timeout) - io.wait_priority(timeout) - mutex.sleep(timeout) Do we want to modify them consistently to accept Float::INFINITY? Consideration 2: C-level API If we want to change the timeout of many methods, we would wish to new C-level API similar to rb_time_interval but can return NULL. Unfortunately, rb_time_interval cannot return NULL because the return type is struct timeval. Note that ext/io/wait/wait.c contains get_timeout function. It seems a good first step for such API. Consideration 3: IEEE 754 dependency. Minor platforms (such as VAX) use non-IEEE 754 floating point numbers without infinity. Note that NetBSD/vax still works. (And there is an emulator, simh). Consideration 4: It seems no major languages accept infinity as select's timeout. I found Perl, Python, and OCaml take a floating point number as a timeout of select function. But they don't accept infinity. -- https://bugs.ruby-lang.org/

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[ruby-core:116085] [Ruby master Bug#20165] Ractors moving a Struct breaks beyond the first 3 fields
by codekitchen (Brian Palmer) 09 May '25

09 May '25

Issue #20165 has been reported by codekitchen (Brian Palmer). ---------------------------------------- Bug #20165: Ractors moving a Struct breaks beyond the first 3 fields https://bugs.ruby-lang.org/issues/20165 * Author: codekitchen (Brian Palmer) * Status: Open * Priority: Normal * ruby -v: ruby 3.3.0 (2023-12-25 revision 5124f9ac75) [arm64-darwin23] * Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- Experimenting with Ractors on ruby 3.3.0, and I'm seeing a bug where if you move a struct between ractors, all but the first 3 fields are set to nil. ``` ruby Foo = Struct.new(:a,:b,:c,:d,:e,:f) r = Ractor.new { foo = Foo[0,0,0,0,0,0] p foo Ractor.yield(foo, move: true) } p r.take ``` ``` ❯ ruby -v ruby 3.3.0 (2023-12-25 revision 5124f9ac75) [arm64-darwin23] ❯ ruby rbug.rb rbug.rb:3: warning: Ractor is experimental, and the behavior may change in future versions of Ruby! Also there are many implementation issues. #<struct Foo a=0, b=0, c=0, d=0, e=0, f=0> #<struct Foo a=0, b=0, c=0, d=nil, e=nil, f=nil> ``` This seems specific to moving, if I set `move: false` the struct makes it across OK. -- https://bugs.ruby-lang.org/

3 2