Folks might find the author’s research paper [1] while at Harvard more informative. This is a great high-level description, but if you want more detail, I recommend the paper.
Huh, I thought the ACM DL was open "now" during the pandemic. Apologies!
That was unfortunately short-lived. ACM announced on March 30, 2020 that they would open their DL for 90 days due to the pandemic [1]. I don't believe there was an extension, so it expired on June 30, 2020.
Note, that there is a new (substantially accelerated) "autoscheduler" implementation in TVM (one of competitors in the article linked), details can be found in https://arxiv.org/abs/2006.06762