[$] Profile-guided optimization for the kernel
One of the many unfortunate consequences of the Covid-19 pandemic was thecancellation of the 2020GNU Tools Cauldron. That loss turned out to be a gain for the Linux Plumbers Conference, whichwas able to add a GNU Tools track to host many of the discussions thatwould have otherwise occurred at Cauldron. In that track, Ian Bearmanpresented his group's work using profile-guidedoptimization with the Linux kernel. This technique, which he oftenreferred to as "pogo", is not straightforward to apply to the kernel, butthe benefits would appear to justify the effort.