Bhyve building kernel....Just an observation

[Willem Jan Withagen]

On 25-10-2014 1:21, Peter Grehan wrote:
> Hi Willem,
>> 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.
> 
>  You'll most likely want to keep some memory and processor resources
> available for the host system. ZFS will need memory for ARC and CPU for
> operations - if these aren't available, it will compete with bhyve's use
> of CPUs, and there will be times when these are conflicting.

Hi Peter,

Thanx for the hint.

The assumption that the performance difference is, is Disk-IO is at
least not very obvious from the simple test.

Both tests were running from a 6Gb tmpfs
Dom0 had 16Gb Ram, and I limited DomU to 12G Ram.

Tested it once in Dom0, and it takes ~ 5Gb of tmp store.
It holds src and obj, and I see no disk traffic while building.

Building kernel with just the default tmpfs (all avail mem + swap)
takes 	6:30 (zfs with ssd's)
versus 	5:30 (tmpfs)

Running in DomU is get about the same difference:
with ahci-hd/zfs backing 	9:30
with tmpfs 			8:30

So I would think the difference is not really in the IO-performance.

But as usual:
	All other opinions more than appreciated.

--WjW