What is the "[system]" process representing ?

[Swift Griggs <swiftgriggs%gmail.com@localhost>]

Folks, I recently installed NetBSD on a Lenovo M83 Tiny machine and from 
time to time, I notice the "[system]" (appears to be a kernel thread?) 
getting up to 80% of the CPU while the box is doing .... nothing. No 
processes are active and a reboot clears the issue (except when it 
doesn't. I power-cycle *then* it's cleared). The only reason I noticed in 
the first place was because of the system-fan spinning up. FYI, this is 
just a standard NetBSD 7 install (not -current).

What is "[system]" really doing? Is there a way to get a more granular 
look at what is going on?

On another system, I have a question about a 1.8Ghz CoreDuo based 32-bit 
i386 laptop with 2GB of RAM. I noticed that '[system]' accumulates the 
most time on the host, but it's never "on the board" when I run top or 
other tools. It's overall usage is trivial. However, I notice that if I 
install debian 8.6 on this machine, I see that 'systemd' (yes, I know it's 
much different and not a kernel process and not apples to apples) is 
_always_ taking between 5-10% of the CPU and is nearly always the #1 
consumer. This is on a fresh installation! I just want to make sure I'm 
not missing some critical fact like perhaps the '[system]' process on 
NetBSD is masking it's CPU usage and is doing the same amount of work 
(doubtful, but possible). This is, after all, a pretty old machine.

So, the basic question is this. Is my x61 ThinkPad actually getting 
slapped around by systemd or is it that system just so slow it's just 
exaggerating an effect that would be hard to detect on a fast/new box? I'm 
trying to rule out some mistake or misconfiguration on my part that a 
systemd advocate (ie.. not me) would point out and say "You just didn't do 
it right."

The corollary is, does NetBSD do the same work but just mask the CPU 
usage? I really really doubt this but I wanted to ask to make sure before 
I make any kind of "linux vs netbsd" claim in this case. 

Man, if that's really the "new normal" for Linux, it's hard to believe. 
I'm tempted to install it on my 500Mhz AMD Geode system. It'd probably 
take up 50% of the CPU if the effect scales... Maybe they don't care 
because they've already eschewed both sysv-init and systemd for 
Busybox-init? Great news for embedded BSD developers, I'd think. :-P

Thanks,
  Swift