Ruby Issue Tracking System

06/11/2026

06:10 PM Ruby Revision 4fb0596b (git): Enable DTrace USDT GC probes in the modular default GC

When Ruby is built with `--with-modular-gc`, the default GC module is
built with `BUILDING_MODULAR_GC` defined.
The existing code stubbed out `probes.h` and `RUBY_DTRACE_GC_HOOK` in
this build path, so any DTrace script attached against... eightbitraptor (Matt V-H)

06:10 PM Ruby Revision f7047b30 (git): Fix Make syntax in Heredoc Makefile snippet

Co-authored-by: Nobuyoshi Nakada <nobu.nakada@gmail.com> eightbitraptor (Matt V-H)

02:25 PM Ruby Revision 8e8682fc (git): Add timeout scale to all macos check CI jobs

MacOS CI jobs are prone to flake on Github Actions with timeouts using
assert_separately.
I had a hunch this was happening a lot, so I had GPT take a look at the last 85
days of macOS CI runs. Here is what it found:
- 36 of 84 macOS CI... eightbitraptor (Matt V-H)

05/20/2026

09:14 PM Ruby Revision 672ef432 (git): Expose monotonic malloc/free totals via GC.stat

eightbitraptor (Matt V-H)

09:14 PM Ruby Revision 8f7e07bb (git): Reorder rb_gc_impl_stat to keep heap_live_slots accurate

Several SETs in rb_gc_impl_stat may allocate a T_BIGNUM RVALUE when
the value exceeds FIXNUM_MAX
This is invisible on LP64 but trips on LLP64 Windows and ILP32 Linux
where FIXNUM_MAX ~= 1.07GB.
If those allocations happen *after* setti... eightbitraptor (Matt V-H)

09:14 PM Ruby Revision cb3b126e (git): Better feature detection for malloc counter locks

eightbitraptor (Matt V-H)

09:14 PM Ruby Revision ed882010 (git): Make sure we flush the cached count to update heap slots

eightbitraptor (Matt V-H)

09:14 PM Ruby Revision 8b7c4342 (git): Snapshot malloc counters at end of sweep

Snapshotting at start of marking lets sweep-time frees count against the
next epoch, which roughly halves GC frequency on alloc-heavy workloads.
Move the snapshot to end of sweep so the next epoch starts from a clean
baseline. eightbitraptor (Matt V-H)

09:14 PM Ruby Revision 4c8f0727 (git): Unify gc_counter_t on rbimpl_atomic_uint64_t

eightbitraptor (Matt V-H)

09:14 PM Ruby Revision 3002cea4 (git): Fix GC Bug in imemo cdhash creation

It's possible for st_init_existing_table_with_size to trigger GC. If
that happens we need to ensure that the table entries count doesn't
contain garbage data, or we'll try and mark random stuff eightbitraptor (Matt V-H)