Determine if an Host has Hypertreading enabled

rtjdamen

@julien-f i have discussed with our developer and i would like to ask you the following

As per their feedback, the XCP-NG API itself gives the double amount of cores per CPU in its output.

For a 2 CPU x 16 core configuration, the system gives 32 cores per CPU, instead of 16.

Please consult with Vates, if they can modify the current API/CPU core count enumeration, to show the actual physical CPU core counts, instead of logical ones in the API output.

julien-f

@rtjdamen Please give me the name of the class field and its value in the XAPI and the same in XO REST API so we can compare.

julien-f

@rtjdamen You'll likely just need to take a look at cpus field and multiply cores and sockets.

rtjdamen

@julien-f Hi julien, the cpu field gives a incorrect view of the real world. because of the hypertreading enabled it gives you double the number of cpu cores there actually is. We are looking for a good way to determine REAL PHYSICAL cores. Reason for that is Microsoft is licensing datacenter licenses on a physical core basis. can u help us with the correct way to find this out?
in Xoa there is a field shown for hypertreading enabled. if that value is shown into the rest api we are there, but if it is not we need a different way to find out if this is enabled or not.

olivierlambert

@julien-f the HT detection we created (via a plugin) is already detecting "threads_per_core" or something like that. IIRC, in XO, if it's >1, we can tell hyperthreading is enabled. So we might need to expose thread per core or something equivalent we did in XO directly in the REST API

julien-f

@rtjdamen REST API now expose the SMT status: https://github.com/vatesfr/xen-orchestra/commit/7fc5d62ca95ba91666f5d5a2268a7871c484ac6a

0

julien-f committed to vatesfr/xen-orchestra

feat(xo-server/rest-api): export hosts' SMT status

Fixes https://xcp-ng.org/forum/post/71374

olivierlambert

Also, we are working to get the info directly in XAPI: https://github.com/xapi-project/xen-api/issues/5462

olivierlambert created this issue in xapi-project/xen-api

closed SMT discoverability: add thread_per_core info in host.cpu_info #5462

rtjdamen

@julien-f do i need to update anything on my end to get this visible? or is this centrally managed?

julien-f

@rtjdamen You need to rebuild your xo-server if you are using it from the sources. I you are using an official XOA, you will need to wait for the next release (last day of the month) and upgrade using the latest channel.

rtjdamen

@olivierlambert is it possible to apply this changes allready to our XOA? it would help with the development.