Maps and Sets

[Sciss]

hi,

what is the purpose of THashMap... i guess it is just for performance reasons? because i use a lot of Ref[ collection.immutable.Map ] and Ref[ collection.immutable.Set ] instances, and they seem to be working fine.

best, -sciss-

[Nathan Bronson]

THashMap allows for concurrency. With Ref[immutable.HashMap] the unit
of conflict checking is the entire map; if two txns both want to update
the map they can't run at the same time. With THashMap the unit of
conflict checking is an individual entry, so the txns can happily run in
parallel so long as they don't conflict on a particular key.

The idea behind THashMap is part of my PhD thesis, in case you're
interested in how it works. THashSet, and sorted variants are coming to
CCSTM.

http://ppl.stanford.edu/papers/podc011-bronson.pdf

- Nathan

[Daniel Spiewak]

  http://ppl.stanford.edu/papers/podc011-bronson.pdf

Well, there goes my weekend!  :-)

Daniel