archiso boots on whatever governor the kernel defaults to, which on most
laptops ramps conservatively. Package extraction and the UKI build are both
CPU-bound, so pin performance for the whole install and put it back afterwards.
Reduced from #87 by @davydotcom, which also disabled every non-POLL cpuidle
state. That half is left out deliberately: C1 wake latency is 1us on current
hardware, and disabling it leaves POLL as the only idle state, so idle cores
busy-spin instead of halting. Package extraction is single-threaded, so on an
8-core laptop that is 7 cores burning power for no work — on a thermally
limited machine that costs the working core its turbo headroom, which is a
plausible way to make the install slower. #87 measured the two tweaks together
with a page-cache prefetch and an updatedb deferral, so the C-state
contribution was never isolated.
Scoped to the whole install rather than just the pacstrap window, which #87
used: finalize_limine_boot runs mkinitcpio and compresses a UKI, and is the
most purely CPU-bound phase there is.
Restoring only matters when an install fails and the user keeps using the live
environment; a successful one reboots out of it.
Co-authored-by: David Estes <davydotcom@gmail.com>
Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>
