Re: [RFC v3 0/5] Transparent on-demand struct page initialization embedded in the buddy allocator

Dave Hansen
2013-08-16T16:36:46Z

Hey Nathan,

Could you post your boot timing patches? My machines are much smaller
than yours, but I'm curious how things behave here as well.

I did some very imprecise timings (strace -t on a telnet attached to the
serial console). The 'struct page' initializations take about a minute
of boot time for me to do 1TB across 8 NUMA nodes (this is a glueless
QPI system[1]). My _quick_ calculations look like it's 2x as fast to
initialize node0's memory vs. the other nodes, and boot time is
increased by a second for about every 30G of memory we add.

So even with nothing else fancy, we could get some serious improvements
from just doing the initialization locally.

[1] We call anything using pure QPI without any other circuitry for the
NUMA interconnects to be "glueless"