Thanks for the excellent summary! For anyone else, I highly recommend reading the paper itself, it's very interesting.
Correct me if I'm wrong, but my interpretation is that this trades memory for speed, so the average memory consumption of Ruby programs would increase. If memory is exhausted, a full 2.0.0-style mark and sweep GC would occur.
Programs that are heavily dependent on C extensions would not see much of a GC speed increase.
Most would, however, and they could continue to improve GC performance piecemeal by moving Ruby classes (starting with common classes like Array or String) to use the new write barrier methods.
Correct me if I'm wrong, but my interpretation is that this trades memory for speed, so the average memory consumption of Ruby programs would increase. If memory is exhausted, a full 2.0.0-style mark and sweep GC would occur.
Programs that are heavily dependent on C extensions would not see much of a GC speed increase.
Most would, however, and they could continue to improve GC performance piecemeal by moving Ruby classes (starting with common classes like Array or String) to use the new write barrier methods.