Yeah, so we could put the parameters back by measuring it in user-space via a nice utility in tools/, and by matching it to relevant hardware signatures (CPU type and cache sizes), plus doing some defaults for when we don't have any signature... possibly based on a fuzzy search to find the 'closest' system in the table of constants.
That would stabilize the boot-to-boot figures while still keeping most of the system specific-ness, in a maintainable fashion.
The downside is that we'd have to continuously maintain a table of all this info, with new entries added when new CPUs are introduced on the market. That's an upside too, btw.
for bigger systems this will also depend on the chipset and even motherboard since inter-CPU communication may go via a 3rd party chip and the speed of that will depend on how far they are apart...
like a 32 socket machine it'll be very different from a 2 socket machine, and from the 32 socket machine from another vendor