On Sat, Feb 03, 2007 at 10:24:04PM -0500, Alan Stern wrote: > On Sat, 3 Feb 2007, Paul E. McKenney wrote: > > > > And another note: this all assumes that STORE-MB-LOAD works "correctly", > > > yes? > > > We have other code which relies on that, should not be a problem. > > > > We have been working with Doug Lea of SUNY Oswego, Sebatian Burckhardt of > > University of Pennsylvania, and Vijay Saraswat of IBM Research towards > > a "universal memory model" that accommodates all machines. Currently, > > it does in fact handle store-mb-load the way we all want, thankfully! > > We should add that many places in the kernel do depend on proper behavior > for this data access pattern. So whatever "universal memory model" we end > up with, it had better handle the pattern correctly if Linux is to support > it.
Agreed! > It's interesting to note, however, that this does exclude simple MESI. Yep! And also a number of compiler optimizations, as it turns out. ;-) There is a tension between nice-to-software memory-barrier properties on the one hand and easily understood code on the other. But I guess that this is true of pretty much any software tool. Thanx, Paul - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/