Re:Wait-free queueing and ultra-low latency logging
by xenadu02 on Thursday May 29, 2014 @01:31PM
(#7817435)
When I read the OP I was thinking exactly along these lines. There are a lot of nifty tricks you can use with atomic compare-exchange.
The Mac/iOS equivalent is the OSAtomicCompareAndSwap family of functions.
For C# users, I wrote about Interlocked.CompareExchange here: http://www.russbishop.net/interlocked-compareexchange. It's one of the few high-level language operations that maps directly to a processor instruction.
If you have side-effect-free mutation functions you can use compexch to merge mutations among multiple threads without locking or blocking, which I've used with immutable snapshots to provide transactional consistency to in-memory objects (without having to pre-check all conditions before mutation or having to create inverses for all operations that can 'roll back' the object mutations). Combined with immutable collections using AVL trees you can get copy-on-write immutable snapshots which is the only real way to deal with massive (50GB+) in-memory datasets that need highly concurrent reads, what-if temporary writes, and permanent writes.
The Mac/iOS equivalent is the OSAtomicCompareAndSwap family of functions.
For C# users, I wrote about Interlocked.CompareExchange here: http://www.russbishop.net/interlocked-compareexchange. It's one of the few high-level language operations that maps directly to a processor instruction.
If you have side-effect-free mutation functions you can use compexch to merge mutations among multiple threads without locking or blocking, which I've used with immutable snapshots to provide transactional consistency to in-memory objects (without having to pre-check all conditions before mutation or having to create inverses for all operations that can 'roll back' the object mutations). Combined with immutable collections using AVL trees you can get copy-on-write immutable snapshots which is the only real way to deal with massive (50GB+) in-memory datasets that need highly concurrent reads, what-if temporary writes, and permanent writes.