TRANSACTIONAL SAPPHIRE

Tomoharu Ugawa, Kochi University of Technology, Japan
Carl Ritson, University of Kent, UK
Richard Jones, University of Kent, UK

This is ahigh-performance implementation of the Sapphire GC algorithm [1,4]. 
It is the first on-the-fly, parallel, replication copying, garbage collector 
for the Jikes RVM Java virtual machine. The implementation provides innovations
such as copying with hardware or software transactions, on-the-fly management of
Java's reference types and simple, yet correct, lock-free management of volatile 
fields in a replicating collector. 

* The jikesrvm directory provides the source code for the Jikes RVM including the
  Sapphire GC.

* The models directory above provides SPIN models [3] of critical components of
  this complicated and highly concurrent system.

For convenience, copies of our relevant published papers are here too:

[1] TOPLAS4004-15 final.pdf
    Tomoharu Ugawa, Carl Ritson and Richard Jones (2018). Transactional Sapphire: 
    Lessons in High Performance, On-the-fly Garbage Collection. ACM Transactions on 
    Programming Languages and Systems (TOPLAS), 40 (4). https://doi.org/10.1145/3226225
    
[2] ismm021-ritson.pdf
    Carl G. Ritson, Tomoharu Ugawa and Richard Jones (2014). Exploring Garbage 
    Collection with Haswell Hardware Transactional Memory. International Symposium
    on Memory management. https://doi.org/10.1145/2602988.2602992

[3] ismm012-ugawa.pdf
    Tomoharu Ugawa, Richard Jones and Carl G. Ritson (2014). Reference Object 
    Processing in On-The-Fly Garbage Collection. International Symposium on Memory
    Management. https://doi.org/10.1145/2602988.2602991

Other relevant publications:

[4] Richard L. Hudson and J. Eliot B. Moss (2003). Sapphire: Copying Garbage
    Collection Without Stopping the World.  Concurrency and Computation:
    Practice and Experience 15, 3–5 (2003), 223–261. https://doi.org/10.1002/cpe.712
    
[5] G. J. Holzmann (2004). The SPIN Model Checker: Primer and Reference Manual. 
    Addison-Wesley.