Kevin Guthrie writing on the Cloudflare blog:
This small and pleasantly-readable function consumes more than 1.7% of pingora-origin’s total cpu time. To put that in perspective, the total cpu time consumed by pingora-origin is 40,000 compute-seconds per second. You can think of this as 40,000 saturated CPU cores fully dedicated to running pingora-origin. Of those 40,000, 1.7% (680) are only dedicated to evaluating
clear_internal_headers. The function’s heavy usage and simplicity make it seem like a great place to start optimizing.
The scale of Cloudflare’s operation is staggering when put in terms like this.