[$] Improving performance with SCHED_EXT and IOCost

At SCALEthis year Dan Schatzberg and Tejun Heo,both from Meta, gave back-to-back talks about someof the performance-engineering work that they do there. Schatzberg presented onthe extensible BPF scheduler, which has beendiscussed extensively on the kernel mailing list.Heo presented on IOCost - a control group (cgroup) I/O controlleroptimized for solid-state disks (SSDs) - and the benchmark suite that is necessary tomake it work well on different models of disk.