Standard_A2_v2 Azure instance will have CPU in offline state

Hi, Sam. Does that only happen in this specific instance type? Can you provide more details? Thanks

Hi Marcelo,
for instance Standard_A2_v2 here, it looks like we're not using for SRU testing anymore, so I will take 5.0.0-1032.34 Bionic Azure kernel for example, the cpu hotplug test from kernel selftest will report that the following instances got some CPU offlined by default:
  * Standard_DS15_v2 (https://pastebin.ubuntu.com/p/Ppw9WQSNMH/)
  * Standard_DS4_v2 (https://pastebin.ubuntu.com/p/Bms5XF4Qxk/)
  * Standard_DS5_v2 (I will skip pasting outputs)
  * Basic_A2

Not sure if this a by-design result (maybe it's how Azure cloud manage its resource?)

But I think this not why the test has failed on them, as it can pass on some other instances even with some CPU offlined by default:
  * Standard_B1ms (only one cpu, test skipped https://pastebin.ubuntu.com/p/xzJb3jVY3g/)
  * Standard_D48_v3 (test passed, https://pastebin.ubuntu.com/p/T7bPKNZ7Pw/)
  * Standard_F32s_v2 (test passed, https://pastebin.ubuntu.com/p/J68CvkZb4Y/)

You can check the test report for azure here http://10.246.72.46/trackers.html (internal link)

hyper-v does not work in the way you are familiar with (such as libvirt) where 2 processor cores are assigned and essentially dedicated to the virtual host.

If i'm not mistaken I believe this is a result in the way hyper-v handles the virtual machines. When a VM is created (BASIC_A2_V2) the hypervisor decides where virtual operating system processes/threads are to be processed via the bare metal resources. I believe this is done at random. This could be why you may be seeing an unusually high amount of cpus in the "offlined" state.

I'm not sure this test should even be run on azure, due to hyper-v. I will take an action item to look into this further. For now, I do not think this is an issue in the least. This test suite is designed to be run on bare metal machines, not hyper-v vms