On Tue, Feb 25, 2014 at 08:32:38PM -0700, Jeff Law wrote: > On 02/25/14 17:15, Paul E. McKenney wrote: > >>I have for the last several years been 100% convinced that the Intel > >>memory ordering is the right thing, and that people who like weak > >>memory ordering are wrong and should try to avoid reproducing if at > >>all possible. But given that we have memory orderings like power and > >>ARM, I don't actually see a sane way to get a good strong ordering. > >>You can teach compilers about cases like the above when they actually > >>see all the code and they could poison the value chain etc. But it > >>would be fairly painful, and once you cross object files (or even just > >>functions in the same compilation unit, for that matter), it goes from > >>painful to just "ridiculously not worth it". > > > >And I have indeed seen a post or two from you favoring stronger memory > >ordering over the past few years. ;-) > I couldn't agree more. > > > > >Are ARM and Power really the bad boys here? Or are they instead playing > >the role of the canary in the coal mine? > That's a question I've been struggling with recently as well. I > suspect they (arm, power) are going to be the outliers rather than > the canary. While the weaker model may give them some advantages WRT > scalability, I don't think it'll ultimately be enough to overcome > the difficulty in writing correct low level code for them. > > Regardless, they're here and we have to deal with them. Agreed... Thanx, Paul -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
