They explain this further on in the Twitter thread. It's the portion of time spent sorting the array of system calls during boot. This didn't used to matter whe

They explain this further on in the Twitter thread. It's the portion of time spent sorting the array of system calls during boot. This didn't used to matter when it took longer than a second to boot up, but now that the boot times are in the sub-second range, the amount of time spent sorting the array of system calls ended up taking up a notable chunk of the time spent booting. Might not matter for the things you care about, but some people certainly do care about boot performance.