On Mon, Aug 29, 2022 at 04:33:23AM +0200, Andrea Parri wrote: > On Fri, Aug 26, 2022 at 05:48:12AM -0700, Paul E. McKenney wrote: > > Hello! > > > > I have not yet done more than glance at this one, but figured I should > > send it along sooner rather than later. > > > > "Verifying and Optimizing Compact NUMA-Aware Locks on Weak > > Memory Models", Antonio Paolillo, Hernán Ponce-de-León, Thomas > > Haas, Diogo Behrens, Rafael Chehab, Ming Fu, and Roland Meyer. > > https://arxiv.org/abs/2111.15240 > > > > The claim is that the queued spinlocks implementation with CNA violates > > LKMM but actually works on all architectures having a formal hardware > > memory model. > > > > Thoughts? > > Section 4 ends with a discussion about certain "spurious" data races. > Do we have litmus tests with them? (I could repro with Dartagnan...) Their Figure 5 clearly shows a data race, but agreed, their claim is that this race is prevented by other code not in this litmus test. Me, I currently suspect that the spurious data race might be due to the failure to guarantee mutual exclusion, though I have not yet read that paper carefully. That is scheduled for tomorrow morning. Thanx, Paul
