TL;DR
If you are not perf-sheriffing you can stop reading here.
I was hoping that would have not been visible (the local benchmarks I tried before landing were noisy), but that was not the case.
Not sure if the GASP alert system realized that already, I think it will do that soon. The regression is linux-only.
So, if you are sheriffing and see an across-the-board perf regression on Linux around #380196, (I guess all page cyclers might be affected) that's me and should go away once
crrev.com/1777363002 lands.
Apology for the inconvenience, I tried to be as much proactive as possible but... perf benchmarks are hard.