begin quoting Andrew Lentvorski as of Tue, Apr 03, 2007 at 08:29:21PM -0700: [atomic syntax] > Congratulations, you just described "Composable Memory Transactions". > > http://research.microsoft.com/~simonpj/papers/stm/stm.pdf
Okay, I've finally gotten around to reading that paper. Clever. > This is one of the cornerstones of Shared Transactional Memory. While an impressive piece of work[1], the problem (as I see it) is that it does not remove the need for locks (but then, nothing will, I think), and it accomplishes the "atomicity" by rollback-and-retry. The second problem would presumably have the realtime guys throwing a fit... given a fast process changing memory and a slow process changing memory, you're going to have a likely case of starvation. Of course, that nailed down the problem of *my* viewpoint in thinking of an "atomic" sequence of instructions -- it simply doesn't work on a multiprocessor or multicore system without introducing locks. So the locks are still there, but they're now hidden behind some syntactic sugar. I'm not sure this would be an improvement. [1] Honest. -- Thoughts on the other paper will be forthcoming, unless my brain melts. Stewart Stremler -- [email protected] http://www.kernel-panic.org/cgi-bin/mailman/listinfo/kplug-lpsg
