You're comparing VMs to bare metal.

Minis only come with a 2 Core processor.

VMs we are able to give more cores to (8) than the bare metal counter part due to better CPUs on Mac Pros.

>  Minis only come with a 2-core processor.

To elaborate, you see 4 due to hyperthreading.

how hard it is to provision machines like these bots that are reported as "cores:8 os:Mac"?

https://chromium-swarm.appspot.com/botlist?c=id&c=os&c=task&c=status&f=os%3AMac&f=cores%3A8&l=100&q=cores%3A8&s=id%3Aasc

> how hard it is to provision machines like these bots that are reported as "cores:8 os:Mac"?

Again, you are comparing VMs to bare metal.

It's 3x as expensive to allocate all Macs as VMs.

> It's 3x as expensive to allocate all Macs as VMs.

this is what I was looking for. Thanks.

Dirk, is it worth it?

To rephrase things: building is basically O(number of cores), and is a bottleneck for what we do. 

Are the 8 cores in the VM 8 real cores or 8 logical / hyperthreaded cores? 

Building is a bottleneck in the CI system, and we will probably be increasingly moving the things that are doing the compile step to bigger and bigger machines, and I expect that to cost more. In this case, I don't think we're talking about that many machines, and so I think it's worth the added expense.

I've filed bug 824543 and bug 824544

> Are the 8 cores in the VM 8 real cores or 8 logical / hyperthreaded cores? 

It's a mix, as the CPU is 12c/24ht @2.7ghz whereas Mac minis are 2c/4ht @3.0ghz.

right, so the 3 VMs per pro are 4c/8ht each. Which is fine, just double-checking ...

Based on the discussions I have had with Vince, I am concerned we do not have enough spare 8 core Mac Pros for this AND a smooth migration path to LUCI. 

Currently, Labs is blocked on getting more Mac Pros (8core) until HWOps moves forward with racking new VMs for DR site. So whatever spare capacity we have now is what we have until at least mid May. 

To ensure we have faster and smooth migrations, we need to have some spare Mac Pro 8core VMs also. 

So with this limitation, will be ok with...

1. Deprioritizing this work until we have more spare Mac Pros 8core VMs (after 2 racks come online)
2. Free up Labs to help with migration needs 
3. Continue to migrate using Mac Minis (4cores) and move bots to 8cores on a case by case basis. 

There isn’t much I can do without bots and this bug is Chrome specific, so updating it accordingly 

Dirk, Labs have provided 16 Macs to luci.chromium.ci and 18 to luci.chromium.try
which builders I should add the bots to?

I think at this point, I've lost the point of this bug. 

It seems like the original question was whether we should reprovision bare metal Minis as 8-core VMs on Pros, and the answer is: no, we shouldn't (minis are generally more cost effective). And, we want to get to a point where we are cleanly able to manage multiple sizes of machines, because we waste a lot of resources running every test on an 8-core VM (nearly all tests run in under 5 min on a single core).

I think maybe there's a separate question, which is: are we doing any builds on minis? If so, we should move those to VMs.

Beyond that, I'm not sure what you'd be trying to do here.

i will return the machines then

filed bug 897363 to return the machines