Peter talked about work-stealing and implementation of runtime systems. We started with briefly discussing a simple implementation of a runtime system, and the scalability problems that you get . There was a brief passage about the optimality of work stealing , to get straight into the new paper about the runtime support for multicore Haskell . At the end we concluded with questioning the premises that seems common: each task is executed exactly once. There is a nice new paper called “Idempotent Work Stealing”  which changes the premise to “each task is executed at least once” and show by microbenchmarks that puts and takes executed on this queue only costs 60% of the Chase-Lev algorithm .