Subj : Re: RCU+SMR To : comp.programming.threads From : Joe Seigh Date : Fri Jul 08 2005 04:50 pm Randy Howard wrote: > Joe Seigh wrote > (in article ): > > >>Sun Research has a whole group that does synchronization, mostly >>lock-free. But I have yet to see any evidence that Sun exploits any of this. > > > > If sun doesn't use it themselves, you can't expect any of their > customers or developer community to do so. They *could* push > it, but they've got bigger fish to fry right now trying to keep > Java alive in the onslaught of alternatives coming along now. > Hmm, they're been pretty busy. Take a look at the USPO published applications page and search on in/herlihy-maurice. They may be trying to patent any reference counting or lock-free algorithm that uses GC ("value recyling") to avoid the ABA problem. It's pretty bad when you are an expert in the area of application and can't figure out what the claims actually say. Herlihy's ROP terminology doesn't help either. .... > >>>Oh well, I guess it will be a long time before this sort of >>>thing is widely used enough to become more generally applicable >>>to portable software. >>> >> >>Well, a killer app will speed things up. > > > True. I've yet to hear of any commercial or popular OSS > application bragging about the massive performance benefits > achieved through the use of lock-free techniques. Real-world > examples convince people more than research papers. Perhaps it > is being widely used but not talked about, or I just missed the > claims? > > Well, Linux used RCU to speed it up. SCO initially claimed IBM stole it from them but I think SCO had no idea what RCU actually was. ANTs Software has a "lock-free" database. They specialize in putting out a press release every month about their "lock-free" database. They have two patents, 6,760,726 System and method of managing concurrent operations on linked lists 6,763,447 Lock-free list for use with computer system utilizing FIFO queue for tracking order of various sublists They look like a LIFO stack using double wide cas with a counter field and a circular FIFO queue of some sort to me but what do I know. I guess databases aren't the kiler app. :) A major open source file server is hitting enough contention on some session tables that they need a lock-free reader/writer solution. There's a debugger for multi-threaded programs that's experiencing serious contention on some AVL trees they use so verify valid storage accesses and they need a lock-free reader/writer solution. These last two aren't desperate enough yet to actually try any lock-free solutions yet but if they're having problems it means others are as well. -- Joe Seigh When you get lemons, you make lemonade. When you get hardware, you make software. .