Bhyve building kernel....Just an observation

[Willem Jan Withagen]

Hi,

Just out of curiosity I did the following:

Updated 10-STABLE src in both Dom0 and in the Bhyve FreeBSD VM
Rebooted my bhyve AMD testing machine so it was in a fresh state.
Nothing special loaded orhter than ZFS.

And build a 10-STABLE kernel on the raw box, that took about 6 minutes.
no {make,src}.conf, so the full GENERIC KERNEL
That took about 6:45 minutes.

Again rebooted to clean the box up.
And then booted a 10-STABLE bhyve VM with all memory and processors 
assigned to the VM. So all the power could be available to the VM.

The build again 10-STABLE in the VM.
That took about 9:30 minutes.

Now it looks like the VM has a 50% overhead.
My expectations were quite a bit better for the performance difference 
between the two?

Would people with more experience in doing VM stuff expect such a large
difference?
Or is this a to be expected result?

Thanx,
--WjW

System info:
Dom0:
	11.0-CURRENT FreeBSD 11.0-CURRENT #1 r273066M
	(110.0 Head with Neel's patch)
	CPU: AMD Phenom(tm) II X6 1075T Processor (3013.83-MHz K8-class
	16 Gb Ram
	ZFS mirror
		2* 500Gb WD WD5000AA
		cache 2* Samsung SSD 840 PRO Series DXM05B0Q

Dom Bhyve
	FreeBSD 10.0-RELEASE-p9
	ahci-hd 16GB